Vision Measurement and Training System and Method of Operation Thereof

ABSTRACT

A binocular viewer, a method of measuring and training vision that uses a binocular viewer and a vision measurement and training system that employs a computer to control the binocular viewer. In one embodiment, the binocular viewer has left and right display elements and comprises: (1) a variable focal depth optical subsystem located in an optical path between the display elements and a user when the user uses the binocular viewer and (2) a control input coupled to the left and right display elements and the variable focal depth optical subsystem and configured to receive control signals operable to place images on the left and right display elements and vary a focal depth of the variable focal depth optical subsystem. In another embodiment, the binocular viewer lacks the variable focal depth optical subsystem, but the images include at least one feature unique to one of the left and right display elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority based on the following U.S. provisionalpatent applications, which are commonly owned with this application andincorporated herein by reference:

Ser. No. 60/776,614, filed by Krenik on Feb. 27, 2006;

Ser. No. 60/791,809, filed by Krenik on Apr. 13, 2006;

Ser. No. 60/796,580, filed by Krenik on May 1, 2006; and

Ser. No. 60/802,362, filed by Krenik on May 22, 2006.

TECHNICAL FIELD OF THE INVENTION

The invention is directed, in general, to optical diagnosis andtreatment devices and, more particularly, to a vision measurement andtraining system and a method of operating the same.

BACKGROUND OF THE INVENTION

There is no question that the ability to see clearly is a most treasuredand valued human ability. Regrettably, many vision disorders commonlyexist. Focusing disorders such as near-sightedness (myopia),far-sightedness (hyperopia) and astigmatism are very common and arenormally treated with prescription lenses (eyeglasses or contact lenses)or refractive surgery. Disorders of the muscles that steer the eyeballsand eye alignment disorders such as strabismus and diplopia are alsowidespread. And finally, retinal disorders such as macular degeneration,diabetic retinopathy and glaucoma affect tens of millions of persons inthe U.S. alone.

Given the broad number of vision conditions that affect the population,it is naturally important that measurement and screening capability beavailable. Of course, a very large number of optometrists andophthalmologists perform vision screening and diagnosis on a dailybasis. These screening and measurement procedures are normally performedin a specialist's office and often include complex and expensive visionmeasurement instruments and time consuming interaction between the careprovider and the patient. Even once they are diagnosed and treated, somevision diseases such as macular degeneration, diabetic retinopathy andglaucoma require ongoing monitoring that demands repeated visits to aspecialist to ensure the disease is remaining under control.Consequently, vision measurement and screening systems that reduce cost,improve accuracy, improve convenience for the care provider or thepatient or improve vision measurement and screening ability in otherways are highly beneficial. And as noted, since certain eye diseasesrequire ongoing monitoring, automatic systems that can store measurementdata, compare it with new measurements and alert patients or careproviders if substantial changes have occurred are also highly desirableand beneficial.

While the need for high quality vision measurement and screening systemsis very well established and accepted, vision training has been a topicof controversy. Vision training, vision therapy, eye exercise, visionexercise, orthoptics and some other terms have been used as names fortechniques that use training techniques to improve vision functionthrough either training of the eye itself, or by training the brain toimprove its interpretation of nerve signals from the eye. In thisdiscussion, “vision training” will normally be used to refer to thesetechniques, but any of the names listed above can be used to refer tothem. In the past, some of these therapies have made claims of “miraclecures” for eye disease and, in some cases, no scientific basis or proofof effectiveness has been available. This has lead some to believe thatvision training is not effective. However, vision training has beenfound to be effective when applied appropriately and for appropriatepatient conditions under a professional care provider's supervision.

In 1999 the American Academy of Optometry and the American OptometricAssociation issued a joint policy statement on vision therapy. Thisstatement can be found in its entirety at the American Academy ofOptometry website at www.aaopt.org, so it will not be repeated here.However, several excerpts are very enlightening. The policy statementstates: “The human visual system is complex. . . . Many visualconditions can be treated effectively with spectacles or contact lensesalone; however, some are most effectively treated with vision therapy.Vision therapy is a sequence of activities individually prescribed andmonitored by the doctor to develop efficient visual skills andprocessing. . . . The use of lens, prisms, filters, occluders,specialized instruments and computer programs is an integral part ofvision therapy.” And finally, it is noted that the policy statementstates that “Research has demonstrated vision therapy can be aneffective treatment for:

Ocular motility dysfunctions (eye movement disorders),

Non-strabismic binocular disorders (inefficient eye teaming),

Strabismus (misalignment of the eyes),

Amblyopia (poorly developed vision),

Accommodative disorders (focusing problems), and

Visual information processing disorders, including visual-motorintegration and integration with other sensory modalities.”

This joint policy statement on vision therapy makes it very clear thatvision therapy or training techniques are effective when properlyprescribed for patients with conditions appropriate for a specifictherapy. Indeed, vision training has become more widely accepted inrecent years. The FDA (Food and Drug Administration) has approved avision training regimen offered by Neurovision Incorporated for thetreatment of amblyopia (www.neuro-vision.com). The American OptometricAssociation website at www.aoa.org explains the use of prisms in thetreatment of strabismus and discusses ways to use vision training intreatment of other vision disorders as well. The effectiveness offixation training (also sometimes called parafovea training oroff-foveal training) which is sometimes used to help patients sufferingfrom macular degeneration learn to make the best use of their remainingvision function is also well established(www.aoa.org/documents/CPG-14.pdf provides a summary of treatments forlow vision including teaching off-foveal viewing with guided practicetechniques).

Hence, it is well established that vision training techniques areeffective when appropriate training regimens are prescribed for certainvision disorders. As would be expected, there have been some attempts toproduce devices and therapies to provide vision training. Liberman, forexample, U.S. Pat. No. 6,742,892 teaches a device with lights at variousdistances from a user to improve focusing ability. Regrettably, suchdevices are somewhat cumbersome, have limited or no ability to measurevision function and are rather boring to operate making it difficult tofully engage a patient in the training regimen. This last issue isespecially problematic for use with children. Mateik teaches a binocularviewer in U.S. Pat. No. 4,756,305 that includes the ability tointerchange prisms and lens to allow for vision training for strabismustreatment and other treatments as well. Regrettably, Mateik's devicecannot measure a patient's vision performance nor adapt automatically tocreate an effective training system. As the lenses are fixed for a giventraining session, only limited ranges and accommodations are possible.Hence, it is clear that vision training devices that offer improvementsover prior art are highly desirable.

Fortunately, computer graphics and gaming technology has now advanced tothe level that low cost, highly effective devices for vision diagnosis,tracking and training can be envisioned. Binocular viewers allow eacheye to be measured or trained independently or together, advances invariable optics allow for changes in focus to be accommodated, computergenerated graphics allow interesting and engaging images to be createdand low cost human input devices allow user feedback information to becollected easily concerning how a user is reacting to a given image orsequence of video.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, theinvention provides, in one aspect, a binocular viewer. In oneembodiment, the binocular viewer has left and right display elements andcomprises: (1) a variable focal depth optical subsystem located in anoptical path between the display elements and a user when the user usesthe binocular viewer and (2) a control input coupled to the left andright display elements and the variable focal depth optical subsystemand configured to receive control signals operable to place images onthe left and right display elements and vary a focal depth of thevariable focal depth optical subsystem.

Another aspect of the invention provides a method of measuring andtraining vision. In one aspect, the method includes: (1) viewing leftand right display elements of a binocular viewer through a variablefocal depth optical subsystem associated therewith and (2) receivingcontrol signals into a control input of the binocular viewer, thecontrol input coupled to the left and right display elements and thevariable focal depth optical subsystem, the control signals operable toplace images on the left and right display elements and vary a focaldepth of the variable focal depth optical subsystem.

Yet another aspect of the invention provides a vision measurement andtraining system. In one aspect, the system includes: (1) a binocularviewer having left and right display elements and a variable focal depthoptical subsystem located in an optical path between the displayelements and a user when the user uses the binocular viewer, (2) acomputer coupled to the control input and configured to provide controlsignals to the binocular viewer that are operable to place images on theleft and right display elements and vary a focal depth of the variablefocal depth optical subsystem and (3) a human input device, the controlsignals being at least partially based on input received from the humaninput device.

Still another aspect of the invention provides a binocular viewer havingleft and right display elements. In one aspect, the binocular viewerincludes a control input coupled to the left and right display elementsand configured to receive control signals operable to place images onthe left and right display elements, the images including at least onefeature unique to one of the left and right display elements.

Still yet another aspect of the invention provides a method of measuringand training vision. In one aspect, the method includes: (1) receivingcontrol signals into a control input of the binocular viewer, thecontrol input coupled to the left and right display elements and thevariable focal depth optical subsystem and (2) placing images on theleft and right display elements, the images including at least onefeature unique to one of the left and right display elements.

Yet still another aspect of the invention provides a vision measurementand training system. In one aspect, the system includes: (1) a controlinput coupled to the left and right display elements and configured toreceive control signals operable to place images on the left and rightdisplay elements, the images including at least one feature unique toone of the left and right display elements, (2) a computer coupled tothe control input and configured to provide control signals to thebinocular viewer that are operable to place images on the left and rightdisplay elements and (3) a human input device, the control signals beingat least partially based on input received from the human input device.

The foregoing has outlined various features of the invention so thatthose skilled in the pertinent art may better understand the detaileddescription of the invention that follows. Additional features of theinvention will be described hereinafter that form the subject of theclaims of the invention. Those skilled in the pertinent art shouldappreciate that they can readily use the disclosed conception andspecific embodiment as a basis for designing or modifying otherstructures for carrying out the same purposes of the invention. Thoseskilled in the pertinent art should also realize that such equivalentconstructions do not depart from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the invention, reference is nowmade to the following descriptions taken in conjunction with theaccompanying drawings, in which:

FIG. 1 shows a user undergoing a vision measurement and/or trainingsession involving a computer, a binocular viewer, headphones and a gamecontroller;

FIG. 2 shows a user and a binocular viewer, the viewing ports, auxiliaryfeatures and features to enhance alignment of the binocular viewer tothe user's face;

FIG. 3A shows a side view of a user's eye and the elements of a displaysystem that is capable of projecting a virtual image such that the imageappears at a different distance, the focal depth, instead of the actualdistance from the user's eye to the actual display screen;

FIG. 3B shows a cross-sectional view of a fluid lens that could be usedto implement an optical subsystem;

FIG. 4 shows a top view of a binocular version of the display systemshown in FIG. 3A illustrating, in particular, the effect that parallaxmay have on how a user perceives the distance to an object;

FIG. 5 shows an image that could be used to measure or train a user'svision acuity at different focal depths;

FIG. 6 shows an image that could be used to measure or train a user'svision acuity in each eye separately while the user is viewing the imagewith both eyes at the same time;

FIG. 7 shows an Amsler grid;

FIG. 8 shows a moving line test;

FIG. 9 shows a crosshair alignment pattern;

FIG. 10 shows a crosshair alignment pattern with a mappeddisease-affected region of a user's eye;

FIG. 11 shows a vision measurement or training game involving incidentand departing lines, a flash is also shown in a disease-affected region;

FIG. 12 shows a vision measurement or training game based on a circularform of computer tennis;

FIG. 13 shows a vision measurement or training game based on firing agun at enemy objects emanating from a disease-affected region;

FIG. 14 shows a view of a three-dimensional, or stereoscopic, imagefitted around a disease-affected region. The surface of the stereoscopicimage includes a target that the user can interact with for parafoveatraining;

FIG. 15 shows how data from multiple games or the same game conducted atdifferent times can be combined to create a single database;

FIG. 16 shows a flow chart of the data processing functions that couldbe used to modify a conventional computer application to incorporatevision training;

FIG. 17 shows a television and control box creating video images for auser based on data gained from vision measurement games; and

FIG. 18 shows a logical interconnection of the elements of a highintegrity vision measurement and training system including security andsystem integrity information to ensure that the system is composed ofproper elements and that they are properly interconnected.

DETAILED DESCRIPTION

One aspect of the invention is directed to a vision measurement andtraining system that includes a computer, a binocular viewer, and ahuman input device. The computer generates video graphics with which theuser interacts. By monitoring the user's responses, the system candiagnose vision conditions, track vision performance and provide visiontraining. Another aspect of the invention is directed to a variablefocal depth function in the binocular viewer that can be controlled sothat focusing disorders can be diagnosed, retinal disorders can be moreaccurately diagnosed and tracked, and vision training can includecontrol of focal depth. Yet another aspect of the invention is directedto special images that provide benefit in vision measurement and/ortraining. Still another aspect of the invention is directed totechniques to ensure alignment of a user's face and eyes to thebinocular viewer are consistent and that any misalignment is eithersignaled to the user or accounted for in collection of vision diagnosisand tracking data. Still yet another aspect of the invention is directedto a vision measurement and training system that can alert a user ifsubstantial changes in their vision function have occurred. Yet stillanother aspect of the invention is directed to system integritytechniques to ensure that the system is properly connected and includesthe proper components so that the system will operate properly.

In FIG. 1, a human user 12 a is shown using a vision measurement andtraining system 11. Throughout this application, it will be understoodthat when a vision measurement and training system 11 is referred to,that the system may be used for vision measurement purposes, visiontraining purposes, or both. The user 12 a is shown wearing a binocularviewer 110 a connected by an electrical cable 18 to a computer 14, suchas a personal computer (PC). The computer 14 is shown fitted with aconventional display 16 that might be a cathode ray tube display, liquidcrystal display panel or any other type of conventionally used computerdisplay. As will be clear, the addition of a conventional display 16 isoptional. Such a display might be beneficial to allow a care provider orother person to observe the system and possibly better interact with theuser 12 a. The binocular viewer 110 a provides images with varyingcharacteristics suitable for vision measurement and/or vision trainingpurposes. While a separate computer and binocular viewer 110 a are shownin FIG. 1, it is possible that electronics miniaturization will allowthem to be a single integrated device. A computer other than a PC may beused to control the vision measurement and training system 11. Forexample, a cell phone, PDA (Personal Digital Assistant), game platform(such as a Playstation® from Sony Corporation, an Xbox® from MicrosoftCorporation, or some other game platform), or other computing devicecapable of generating images, receiving user feedback and storing datacould all possibly perform the function of the computer 14 in FIG. 1.

The vision measurement and training system 11 as shown also includes akeyboard 15 and a game controller 112. These devices allow the user 12 aor a care provider (care provider is not shown in FIG. 1) the ability tofeed signals to the computer 14 that allows the system to assess thevision capability of the user 12 a, control ongoing measurement,tracking or training routines and record results. The game controller112 is shown connected to the computer 14 with an electrical cable 114.Other human input devices besides keyboards and game controllers canalso be used to allow the user 12 a to feed signals to and control thecomputer 14. Examples include joysticks, microphones, a mouse, touchpads, foot pedals, steering wheels and all other possible human inputdevices. Speech recognition or voice recognition devices may be used forhuman input and could be important for persons who may have difficultyin operating other types of devices (for example, users withcoordination problems, arthritis, or other conditions). The addition ofhuman input devices allows the user 12 a to react to images and feedsignals to the vision measurement and training system 11. This feedbackinformation can be used to allow the system to measure the vision of theuser 12 a and adapt training to their specific needs. It also allowsstatistics on the performance of the user 12 a to be measured andpossibly logged. Simple gaming examples with simple scoring arepossible, but very sophisticated information on how rapidly the user 12a can focus, the limits of their focus both in depth and laterally,information on how sensitive and effective various areas of the retinaare in sensing light and color, information on how the vision of theuser 12 a is affected by light intensity and many other usefulmeasurements and statistics can be collected. It is also possible forthe system to keep logs on when a given user 12 a used the system, forhow long and with what results. Clearly, this information could be veryuseful to a care provider monitoring the vision capability of the user12 a or could be useful in allowing the system to adjust training basedon past results.

FIG. 1 also shows headphones 116 connected to the computer 14 by anelectrical cable 118, so that audio stimulus may be included. Otheroptions for audio stimulus include speakers on the computer, speakers onthe binocular viewer 110 a, external speakers, or other methods. Audiocan enhance the user 12 a experience and benefit vision training byenhancing the concentration of the user 12 a on various aspects of avideo image. Stereoscopic audio, surround sound, 3D audio effects andthe like can all be effectively applied. It should be clear that otherstimulations that are common in video gaming systems can also beapplied. These include vibration effects through the game controller112, auxiliary lighting, motion or vibration of the chair (not shown inFIG. 1) of the user 12 a and any other possible stimulation of the user12 a. It is noted that while the binocular viewer 110 a, headphones 116and the game controller 112 are shown connected with electrical cables,that other connections including wireless connections for these devicesare also possible. If electrical cables are used, it may be possible tocombine some of them into shared or combined cable connections.

FIG. 2 shows a user 12 b and a binocular viewer 110 b. Throughout thispatent application, the user 12 b and the binocular viewer 110 b will beconsidered equivalent to the user 12 a and binocular viewer 110 a ofFIG. 1. The purpose of FIG. 2 is to clarify several detailed aspects ofthe binocular viewer 110 b and how it is fitted to the user 12 b, butthe operation and use will be within the vision measurement and trainingsystem 11 of FIG. 1. Hence, while different in appearance and level ofdetail shown, the binocular viewer and user of FIG. 1 and FIG. 2 areequivalent. In FIG. 2, the binocular viewer 110 b is shown in front ofthe face of the user 12 b. Of course, the user 12 b actually wears thebinocular viewer 110 b in actual use and they are shown apart only sothat some details of the viewer can be made visible. The binocularviewer 110 b includes a head strap 22 to securely mount the binocularviewer 110 b to the head of the user 12 b. The head strap 22 is shownonly on the left side of the viewer and is not shown as a completedstrap to avoid unnecessary clutter in the drawing. Of course, othermounting techniques such as semi-rigid head mounts, harnesses, helmets,or other methods are also possible. Desktop stands, wall mounting orother support systems may also be used. Whatever method is used to mountthe binocular viewer 110 b, it is important for some vision measurementsthat the face and eyes of the user 12 b be accurately and consistentlyaligned to the binocular viewer 110 b. Special features to enhanceaccurate and consistent alignment are possible such as the head piece210, temple pads 216 and nose pieces 26 shown in FIG. 2. These and otherpossible alignment devices may be fixed or adjustable to enhance fit,comfort and alignment. As will be described later, the visionmeasurement and training system 11 may include eye tracking or otherautomatic techniques to determine if the binocular viewer 110 b isaccurately aligned to the face and eyes of the user 12 b and eithersignal the user 12 b to correct misalignment or possibly make electronicadjustments to the collected data to account for small misalignments.

The user 12 b in FIG. 2 views images through the viewing ports 24. Theviewer may also include auxiliary lights within the viewer such aslights 28 and 214. These auxiliary lights may be used in some visionmeasurements to draw the eyes of the user 12 b to a specific directionor to assess how a user 12 b reacts to light stimulus outside the normalfield of view of the binocular viewer 110 b. While auxiliary lights 28and 214 are shown in the outside periphery of the binocular viewer 110b, they could be placed anywhere the user 12 b can see while wearing thebinocular viewer 110 b. Another useful feature for vision measurementand training is an eye tracking device. In FIG. 2, binocular viewer 110b includes an optional video camera with lens 212. This video camera maybe used to monitor the eyes of the user 12 b so that eye trackingsoftware and hardware either within the binocular viewer 110 b or withinthe computer 14 shown in FIG. 1 may provide the vision measurement andtraining system 11 with information regarding the direction that theuser 12 b is looking at any given time. Eye tracking devices andtechnology are well established and the details of their operation willnot be described here. Some binocular viewers 110 b may includeadditional auxiliary displays in the peripheral regions of the viewer toextend the ability to provide visual stimulus beyond the viewing ports24. Other features inside the binocular viewer 110 b might include avibrator to massage the area around the eyes of the user 12 b, a heaterto warm and sooth the eyes of the user 12 b, a humidifier to keep theeyes of the user 12 b moist, or other possible features to enhancecomfort or contribute to vision measurement or training. Andadditionally, some binocular viewers 110 b may include gyroscopes,accelerometers, or other motion sensing devices so that movement of thehead of the user 12 b can be sensed and accounted for.

In addition to the binocular viewer 110 b shown in FIG. 2, other methodsof generating images suitable for measurement and training are alsopossible. However, alignment to the eyes of the user 12 b should beaccounted for if measurements related to vision acuity in particularareas of the visual field are to be performed. This alignment can beaccounted for mechanically as illustrated in FIG. 2 or as noted, by eyetracking as with camera with lens 212 in FIG. 2 or through electronicanalysis and correction of the data as will be described later. Also, itis essential for some vision measurements that each of the eyes of theuser 12 b be assessed separately. Hence, other methods suitable forgenerating images for vision measurement and training include glasseswith light shutters synchronized with a display (this is cumbersome andrequires large shutters for the display that are not conventionallyavailable), use of polarized light and polarized lenses to separateviews for each eye (requires a polarized display that is notconventionally available), use of light of different colors and coloredfilter eye glasses (this constrains the ability to measure sensitivityto color), holographic display technology (expensive and laser lightmakes it very difficult to measure focusing ability), or other methods.Each of these methods has some serious drawbacks as noted and all ofthem suffer from lack of an ability to easily and consistently adjustfocal depth as will be explained later for the binocular viewer 110 b.It is also possible to provide a system without binocular capability,however this would substantially detract from the breadth of possiblemeasurements and vision training that could be offered.

FIG. 3A, FIG. 3B and FIG. 4 show part of the internal construction ofthe binocular viewer 110 a and 110 b shown in FIG. 1 and FIG. 2,respectively. As noted previously, these are equivalent, so forsimplicity, this application will normally refer to them only asbinocular viewer 110 b. FIG. 3A shows a side view of a human eye 310 andthe elements of a monocular display system. In this preferredembodiment, the monocular display system shown in FIG. 3A would beincorporated into each side of the binocular viewer 110 b that is shownin FIG. 2. In FIG. 3A, a display element 32 generates an image 34 thatpasses through an optical subsystem 38 and then passes on to the humaneye 310. Light rays 36 are included in FIG. 3A for illustrativepurposes. The image 34 is shown in FIG. 3A slightly in front of displayelement 32 since the FIG. 3A is a side view and it cannot be illustratedotherwise. Of course, in a real system, the image 34 would be projectedfrom the surface of the display element 32 that is facing the human eye310. The display element 32 is a liquid crystal display (LCD) in thispreferred embodiment. However, other display technologies such as plasmadisplays, OLED (Organic Light Emitting Diode), cathode ray tubes, laserdisplay systems, MEMS (Micro Electro Mechanical System), and many otherdisplay technologies could also be used. Additionally, the displayelement 32 might not consist of a single element, but might also includemirrors, lens, optical fiber, lasers, or other optical devices thatallow an image to be created in some other location and the imagedisplay to be projected in a manner to achieve the same effect for theuser 12 b as shown in FIG. 3A. The optical subsystem 38 processes theimage 34 so that the human eye 310 will see the virtual image 314 infocus seeming to appear at a distance equal to the focal depth 312. Ofcourse, the virtual image 314 is the only representation of the image 34that the human eye 310 actually perceives. The optical subsystem 38might be formed with mirrors, prisms, lens, optical sensors, digitaloptical processors, fluid lenses, moving mirrors, moving lenses, MEMSstructures, deformable lenses, micro mirrors or other elements. Theoptical subsystem 38 is responsive to electronic control so that theeffective focal depth 312 that the virtual image 314 appears at can bevaried by control either from the binocular viewer 110 b or the computer14. It is also possible with certain constructions of the opticalsubsystem 38 that focal depth of the optical subsystem 38 can be variedas a function of circumferential location so that astigmatism can begenerated or compensated. Astigmatism can also possibly be addressed bymonitoring the effect of different focal depths to the user 12 b as afunction of location within the field of view of the user 12 b.

In FIG. 3B, a cross-sectional view of an embodiment of optical subsystem38 consisting of a fluid lens 316 is shown. As noted above many otherembodiments of the optical subsystem 38 are possible. In FIG. 3B,transparent windows 320 a and 320 b contain two fluids which have beenselected so that they don't normally mix with each other. The firstfluid 322 is normally a conductor such as water containing ions and thesecond fluid 318 is normally an insulator such as oil. First electrode326 contacts the first fluid 322 and insulator 328 separates secondelectrode 330 from the fluids. As the potential voltage across firstelectrode contact 324 and second electrode contact 325 is varied, thepotential from first electrode 326 and second electrode 330 varies.Since first electrode 326 is in contact with first fluid 322, thepotential between first fluid 322 and second electrode 330 is alsovaried so that the electrostatic potential between them alters the shapeof the interface between first fluid 322 and second fluid 318. In thisway, the focal length of fluid lens 316 is responsive and variable basedon the potential voltage applied across first electrode contact 324 andsecond electrode contact 325. Refraction of light entering transparentwindow 320 a from the left of FIG. 3B passing through fluid lens 316 andexiting transparent window 320 b will be refracted by fluid lens 316 byan amount that is variable based on the potential voltage across firstelectrode contact 324 and second electrode contact 325. Clearly, fluidlens 316 if applied in FIG. 3A will provide the necessary function ofproviding a variable focal length optical function that is responsive toelectronic control.

Throughout this patent application, the term adaptive focal depth shallmean the ability to control the focal depth 312 electronically. Thisterm is used regardless of the specific construction of the binocularviewer 110 b and whether the control is from the computer 14 or isgenerated internally within the binocular viewer 110 b itself. As willbe explained later, adaptive focal depth may be used in the visionmeasurement and training system 11 to automatically compensate forrefractive disorders, adjusting the focal depth 312 to correspond toother aspects of an object that contribute to the distance at which theuser 12 b perceives it, or to intentionally keep an object out of focusfor a specific purpose. Adaptive focal depth may be used by the user 12b to control the focal depth 312 manually through the game controller112 or other human input device connected to the vision measurement andtraining system 11. Adaptive focal depth may also be used by the visionmeasurement and control system 11 to automatically create desiredcombinations of focal depth, parallax and perspective in an image.

In this preferred embodiment the optical subsystem 38 providescapability to allow the focal depth 312 to be varied. However, for somevision measurements and training, a fixed focal depth 312 is acceptable.For example, when dealing with eye diseases that primarily impact theretina (for example, macular degeneration) it may not be important tovary the focal depth 312. In such a case, a display with a fixed focaldepth 312 could be used. However, even in such cases where variablefocal depth 312 is not strictly essential, it can still be beneficial tovary the focal depth 312 to account for any focusing disorder the user12 b may suffer. That is, the vision measurement and training system 11can account for the need for minor adjustments to the focusing abilityof the user 12 b (for example, nearsightedness) so that very sharp andclear images result leading to more accurate vision measurements. It mayalso be beneficial to vary the focal depth 312 to exercise and relax theeye's 310 focusing mechanism so that possible eye strain related toviewing at a constant focal depth may be reduced.

It is noted that as the optical subsystem 38 is used to change the focaldepth 312 of the image, that some variation in the perceived size of theimage may occur. Whether this is a problem depends on how the opticalsubsystem 38 is constructed and on the type of vision measurement ortraining being undertaken. However, since the display element 32 isunder computer control, it is possible to simply adjust the size of theimage as generated on the display element 32 to counter act any changein the size of the virtual image 314 as the focal depth 312 is varied.Clearly, this adjustment to image size is optional and whether or not itis included is a function of the desired images to be generated.

In FIG. 4, a top view shows some details of the internal construction ofbinocular viewer 110 b. As discussed above with regard to FIG. 3A, thebinocular viewer 110 b of FIG. 2 includes the monocular system that isillustrated in FIG. 3A in front of each eye of the user 12 b, and thisconstruction is further illustrated in FIG. 4. The left eye 416 of auser 12 c views the image pictured on the left display element 48 as thevirtual image of the binocular display system 424. The image pictured onthe left display element 48 is produced on the left display element 44and is processed by the left optical subsystem 412. Similarly, the righteye 414 of the user 12 c views the image pictured on the right displayelement 46 as the virtual image of the binocular display system 424.And, the image pictured on the right display element 46 is produced onthe right display element 42 and is processed by the right opticalsubsystem 410. The virtual image of the binocular display system 424appears to the user 12 c at the focal depth of the binocular displaysystem 422. As noted above with regard to the monocular system of FIG.3A, the focal depth of the binocular display system 422 is variableunder automatic control in this preferred embodiment through control ofthe right and left optical subsystems 410 and 412, but it is alsopossible to provide a system beneficial for some measurements ortraining that uses a fixed focal depth.

As noted above, the right and left optical subsystems 410 and 412,process the image so that the virtual image of the binocular subsystem424 appears in focus at a distance equal to the focal depth of thebinocular display system 422. Additionally, in the binocular displaysystem shown in FIG. 4, the angle that the images are viewed at for eacheye also contributes to the perception of distance that the user 12 cexperiences. In this preferred embodiment, the angle between the leftline of sight 420 and the right line of sight 418 will be adjusted tocorrespond to the focal depth of the binocular subsystem 422 so that theuser will not see multiple images, a single image out of focus, or otherimpairments, but rather, will see the virtual image of the binoculardisplay system 424 in focus and correctly. The angle of the lines ofsight of a user's eyes to a viewed image is commonly referred to asparallax and this term will be used herein. The position of the imagepictured on the left display element 48 and the image pictured on theright display element 46 can be adjusted to be closer or further fromthe binocular display system virtual center line 426 so that the anglebetween the left line of sight 420 and the right line of sight 418 willcorrespond to the focal depth 422 and the user 12 c will perceive thefocal depth and parallax of the image to be consistent. It is noted thatsince the distance between each individual user's eyes is different,this information may need to be determined by a calibration routine orotherwise it could simply be entered into the system. Clearly, forparallax and focal depth to be properly coordinated, the distancebetween the eyes of the user 12 c should be accounted for. In athree-dimensional (3D) binocular viewer such as the one illustrated inFIG. 4, the images provided to each of the eyes of the user 12 c isslightly different as the user will see the virtual image from adifferent perspective from each eye. This is a very common techniqueknown as stereoscopic vision and it will be used in some of themeasurement and training techniques herein. It is noted that unlike thedrawing in FIG. 4 that shows the image pictured on the left displayelement 48 and the image pictured on the right display element 46 asidentical images. If stereoscopic vision is used, these images should beslightly different to account for the different perspective view eacheye would see if a real object were present at the location where thevirtual image of the binocular display system 424 is perceived to be. Inthis way, a binocular viewer 110 b allows the user to see a seeminglyreal 3D image if stereoscopic vision is used.

In addition to parallax and focal depth as described above, otheraspects of human vision also affect the distance a person perceives to agiven object. Perspective, for example, is the way one views closerobjects to be larger, more distant objects to be smaller, and parallellines in an image to converge at a vanishing point in the distance. Ofcourse, perspective is very well known and won't be discussed in detailhere. Another aspect of how far one perceives things to be away iscalled motion parallax. Motion parallax is the effect that objects closeto us appear to move past us faster than do more distant objects. Otheraspects such as lighting, shadowing, absolute size of familiar objects,and other effects also play a role. Hence, there are many aspects tomaking an image appear to have true depth. For the purpose of simplicityherein, parallax will only be referred to specifically with regard toFIG. 4, perspective and focal depth. It is understood that other knownadditional techniques may be applied and may be necessary to create afully realistic image as would be beneficial for some of the techniquesdescribed.

The vision measurement and training system 11 including binocular viewer110 b with adaptive focal depth, that is with the internal constructionshown in FIG. 4, is capable of measuring or training the eyes of theuser 12 b in multiple ways. The parallax and focal depth of the virtualimage can be made consistent so that the user 12 b sees a very real 3Dimage that includes the depth and perspective a real object would ifsimilarly viewed. Focal depth 312 can be adjusted separately for each ofthe eyes of the user 12 b so that symmetry problems with vision can beaddressed. The vision measurement and training system 11 of FIG. 1 iscapable to measure or train the eyes of the user 12 b in a very complexand sophisticated manner. Visual field, refractive errors, astigmatism,retinal disorders, double vision, and many other vision measurements canbe performed, and, where appropriate, vision training may also beundertaken. For example, the binocular system as described can varyfocal depth for each eye and parallax separately so that diplopia(double vision) caused by a refractive disorder can be compensated sothat binocular vision is reestablished, allowing other measurements ortraining to be undertaken. Moving images laterally in the same mannerthat prism therapy is used for treating strabismus is also possible.Very many measurements and training regimens are possible.

Another benefit of the binocular viewer 110 b with adaptive focal depthis that since the perspective, parallax and focal depth of an object ofinterest within an image can all be consistent with each other, the user12 b will not normally sense something unnatural about the images he/sheis viewing. This is potentially very important as an issue withconventional binocular viewers is that users 12 b sometimes experienceheadaches, dizziness, or other discomforts when using them. As thebinocular viewer 110 b with adaptive focal depth provides more naturalimages, it is possible that some users 12 b will experience lessdiscomfort when such a viewer is used. This benefit is similar to thewell known situation that a person with an incorrect eyeglassesprescription may suffer headaches, dizziness and other possiblediscomforts. By ensuring correct accommodation for the image beingshown, enhanced user 12 b comfort is clearly possible.

In spite of the sophistication of the binocular viewer 110 b, it isstill not capable to provide a perfectly realistic view of a real worldimage. Herein, an image is the complete scene a user 12 b sees throughbinocular viewer 110 b and to objects within the image as individualfeatures, items or elements within the image. For example, a view down astreet is an image, but each car parked along the street is an object.In the real world, of course, all objects within an image are not at thesame distance. Consequently, each object in an image has differentparallax depending on its distance from the person viewing it and theangle it is viewed at. And, of course, the focal depth is different foreach object in an image depending on its distance from the personviewing it. It is possible that the optical subsystem 38 as shown inFIG. 3A could be eventually so sophisticated as to make each object in afull image to have a different focal depth 312 so that the eye wouldhave to adjust its focus for each object just as it does in the realworld. If this capability were available, it would then only be neededto alter the position of the objects in the images in the two displayelements shown in FIG. 4 so that the parallax of each object was alsocorrect and a near perfect, real-world, image could be created.

However, since the vision measurement and training system 11 is based onproperly viewing objects at different distances, locations andorientations, it is important that the object of particular interest inan image have the desired parallax, perspective and focal depth. Thiseffect can be achieved by making the object of interest capture theattention of the user 12 b so that other objects in the image that willinvariably have different levels of error in their parallax and/or focaldepth are not so noticeable. For example, in a video game where the user12 b is shooting virtual bullets at an enemy plane, the enemy plane isthe object of primary interest to the user 12 b. If the parallax andfocal depth are correct for the user 12 b, the eyes of the user 12 bwill alter their focus as the enemy plane moves in the field of view andmoves to varying distances. The enemy plane in such a case might beshown in bright colors and with crisply defined features. In contrast,the background scenery, sky, landscape, and other objects in the displaymight be portrayed in duller colors and might be intentionally blurredto make them less interesting to the user 12 b. In this way, the visionmeasurement and training system 11 can achieve its goal to measure andtrain the eyes of the user 12 b without requiring a perfect displaysystem, but rather with the practical binocular viewer 110 b includingthe internal construction shown in FIG. 4 that can be produced withexisting technology.

Now that the construction of the binocular viewer 12 b is understood, itis possible to explain how vision measurements can actually take place.In FIG. 5, a video display image 51 is shown that could be used for thispurpose when viewed through binocular viewer 110 b. Within the displayscreen boundary 52 in FIG. 5, there are nine box images. Each box exceptone has a cross on its front surface that extends diagonally from cornerto corner. The upper row of box images 54 includes three boxes thatappear at the furthest distance from the user 12 b. The middle row ofbox images 56 includes three boxes appearing at a medium distance. Andthe lower row of box images 512 includes three boxes that appear closestto the user. It is noted that through a binocular viewer 12 b, the imageof FIG. 5 would appear to have real depth as a true stereoscopic visionimage would be provided. As patent applications are limited to flatdrawing sheets, the perspective drawing in FIG. 5 is the best that canbe provided. It should be clear that in a real system, again using abinocular viewer 110 b, the parallax and perspective of each box in FIG.5 would be correct so that a very realistic image would be visible. Atarget 58 is shown on the left most box in the middle row of box images56. In the measurement used with the image of FIG. 5, the various boxesare highlighted and a target 58 appears on each of them randomly overtime. Only one box has a target 58 on it at a time, all the others havecrosses. The strategy for the measurement is for the user 12 b toquickly point a cursor or crosshair on the target and detect the imagewith whatever human input device is available as rapidly as possible.The system then logs the delay and the accuracy with which the user 12 bcompleted this task and determines a performance score. As the target ismoved from one row to another, the focal depth of the binocular viewer110 b is altered to correspond to the perspective and parallax of theboxes in that row. In this way, the ability of the user 12 b to focus atvarying distances can be assessed. Over the course of many suchmeasurement sequences, the system can develop a composite score for theuser 12 b and can assess the ability of the user 12 b to play the game.Range of focus, time to focus, refractive correction needed, and time toassess a target are only some of the many measurements that can berecorded.

The target 58 shown in FIG. 5 is a simple circular target forsimplicities sake, but it is clear that a more sophisticated targetcould be used. For example, the capital letter E is sometimes used forvision focusing assessment in which the person under test is asked by anoptometrist to state which direction the letter is rotated (the normallyhorizontal elements of the capital E that normally point to the rightmay point up, down, or to the left or right) to determine the person'sability to focus at a given distance and text size. By replacing thesimple circular target 58 in FIG. 5 with a capital E scaled to varioussizes and at different distances depending on which row of boxes itappears and asking the user 12 b to signal the orientation of the lettereach time it appears, the simple game described above in FIG. 5 isclearly extended to be very similar to a professional vision assessmentfrom an optometrist. Of course, it is also possible to direct a user 12b to view a particular object and simply adjust the focus, through thegame controller 112 or other human input device used in the visionmeasurement and control system 11, much as one would with a pair ofbinoculars and then simply record the focal depth settings to assess thevision of the user 12 b.

It is noted that in a gaming feedback system such as the visionmeasurement and training system 11 described herein, that reaction timeand errors made by the user 12 b should be accounted for. Clearly, thetime taken for the user 12 b to acknowledge a target 58 in the gameexplained with regard to FIG. 5 includes not only the time needed tofocus on and recognize the target, but also on the human reaction timeto acknowledge the target 58 via the human input device. However, thesystem can easily measure reaction time by engaging the user 12 b towatch a single box and simply acknowledge the target 58 each time itblinks or changes size, shape, etc. In this way, reaction time apartfrom focusing time or ability can be assessed. It is also clear that theuser 12 b will occasionally make an error and acknowledge a target 58before it has been fully recognized or possibly be distracted and delayan acknowledgement. However, since the system would take many dozens oreven hundreds of measurements to assess vision performance, it ispossible to generate statistics, determine a standard deviation of thetime to acknowledge a target 58 as a function of range and location andsimply eliminate any deviant or erroneous measures from the database.

The vision measurement and training system 11 can also use the image ofFIG. 5 for vision training. Through the measurement sequence describedabove, the vision acuity of the user 12 b as a function of distance canbe assessed so that the level of accommodation (strength of externallenses the user requires to see clearly and in focus) the user requiresfor each row of boxes is known. With this information, many possibletraining regimens are possible. For example, the vision measurement andtraining system 11 may provide the user 12 b with slightly lessaccommodation (in an absolute sense) than is normally required for eachrow of boxes so that the user 12 b is forced to use their own eye'sfocusing ability. In this way, the user 12 b is forced to strugglesomewhat to focus at all ranges and trains his or her eyes to focus attheir limit. It is important that for such a training regimen that theuser 12 b only be requested to struggle mildly to focus as, if too muchis demanded, the user 12 b will simply not be able to see adequately andmay give up the game. The appropriate level of focus to demand of theuser 12 b can clearly be determined by altering it over some range andnoting the user 12 b responses and ability to play the game. Hence, theability to continuously assess the focusing ability of the user 12 b andto pace the progress of the training to his or her present ability is akey important aspect that is only possible with a mechanism for adaptivefocal depth 312 as described above. The system for adaptive focal depthis also beneficial in that it can allow the user to be forced tostruggle somewhat at all ranges. In this way, the user is constantly(albeit mildly) challenged so that the training may be more effective.It is also noted that this ability to force the user 12 b to struggle tofocus could be limited to one eye. If only one eye is to be trained inthis way, the image in front of the other eye may carry only a vestigeof the target image to help the user 12 b maintain a sense ofperspective and parallax, while forcing the eye being trained to bearthe burden of accurate focusing. It is also possible to show a partialview of the video display image 51 of FIG. 5 to the eye not beingtrained and a complete image to the eye being trained. For example, theeye not being trained might be offered the video display image 51 of theboxes without either the target 58 or the crosses on their front faces.The eye being trained would receive the full image with the targets 58and crosses so that the full training burden would fall to that eye. Inthis way, the eye not being trained would see enough of the videodisplay image 51 that the user would maintain a comfortable sense ofparallax and perspective while not in any way helping the user 12 b inresponding to the stimulus of the target 58.

This scheme can be taken further with a video display image of pointedobjects 61 as shown in FIG. 6. In FIG. 6, within the display screenboundary 52, pointed objects are displayed with the binocular viewer 110b and are positioned and oriented so that only one of the eyes of theuser 12 b sees some of the surfaces of the pointed objects. This isillustrated in the lower row of pointed objects 68 where a target on aside of a pointed object 610 is shown on the left side of the left mostpointed object. While it is, again, not possible to fully portray thenature of the 3D stereoscopic vision image on a flat drawing sheet, itis clear that the image could be configured so that the target on a sideof a pointed object 610 would only be visible in the left eye of theuser 12 b. This is illustrated, to the degree possible, with the middlerow of pointed objects 66 where longer points have been used so that asdrawn in perspective, some sides of the pointed object cannot be seen.Of course, with a binocular viewer 110 b, some portion of the otherwisenot visible parts of the objects would become visible to one of the eyesof the user 12 b. FIG. 6 also includes an upper row of pointed objects64 to better show how the overall image includes objects at variousdistances. Using the video display image of pointed objects 61, and thegame sequences described above with regard to FIG. 5, it is clear thatthe user 12 b would unwittingly provide information through his or hergame play regarding the vision of only one of his or her eyes at a timedue to the clever location of objects in the 3D image where only one eyecan actually see them. This capability is particularly important forusers 12 b that have asymmetry in their vision (one eye hassubstantially different vision ability than the other), convergenceproblems, or difficulty with fusing (combining) the view from each oftheir eyes into a single neural image. Clearly, the technique of FIG. 6is quite beneficial in such cases as the user 12 b views a single andvery natural image while each eye can be measured separately.

Of course, many additional aspects of vision acuity can also be measuredwith the vision measurement and training system 11 described herein.While the system could be implemented in monochrome, the use ofpolychrome (i.e. color) displays allow the system to assess visualacuity as a function of color. By changing the rate at which an imagechanges, the ability of the user 12 b to focus rapidly could bemeasured. With more sophisticated images, the ability of the user 12 bto maintain focus as an image moves laterally or closer or further fromthe user 12 b could be assessed. Vision acuity as a function of motion,color, brightness, focus, speed, location on the retina, contrast andmany other possible aspects can be measured and appropriate trainingregimens can be developed. Even aspects of vision that require adistortion in the image or optics of the binocular viewer, such asastigmatism, may be measured.

It is noted that the video images, shown in FIG. 5 and FIG. 6 are verysimple examples used to illustrate how the system can assess and trainthe vision of the user 12 b. Clearly, much more complex, changing andinteresting images and all possible ranges (distances to the objects)can be used. The simple boxes and pointed objects of FIG. 5 and FIG. 6can be replaced with much more interesting shapes. Animals, flowers andother interesting objects can be included to create very interestingimagery that would appeal to whatever age group the given system isintended for. In this way, a system that provides images much more likethose found in nature or in a modern video gaming system can provide thesame results while offering the user 12 b a much higher level ofenjoyment. Of course, the system can also use other information to morerapidly and accurately assess the vision capability of the user 12 b.This information can include the vision information of the user 12 bthat was determined on prior occasions that the user 12 b made use ofthe system, and that information can be automatically logged and storedin the computer 14 for such future use. Other information could beinformation that the user 12 or a care provider might enter into thesystem regarding specific aspects of the measurements or training thatthe care provider wants to control or influence. In some cases, the careprovider might want to maintain complete control of the visionmeasurement and training system 11 and operate the system manually whileverbally questioning the user 12 b, much as an optometrist works with apatient today.

While useful for many vision conditions, FIG. 5 and FIG. 6 dealtprimarily with vision measurement and training with respect to focusingdisorders. However, a very important class of vision disorders relatesto retinal function. Macular degeneration, diabetic retinopathy,glaucoma and other retinal disorders are vision disorders that may beassessed by how well a patient can see throughout their visual field.Measurement, tracking and training are all very important for this classof vision disorders and the vision measurement and training system 11provides novel ability to provide these benefits. In FIG. 7, the wellknown Amsler grid 71 is presented. The display screen boundary 52represents the edge of the field of view of the binocular viewer 110 bin this preferred embodiment. The grid lines 74 form grid segments inthe crossing vertical and horizontal square grid pattern (square gridsare normally used, but rectangular, triangular and other grids are alsopossible) The center square 72 is also clearly shown. The Amsler grid 71is widely used as a simple diagnosis mechanism for macular degenerationand other retinal disorders. Normally, a paper grid is used and thepatient simply covers one eye and looks at the center square 72. Whilelooking at the center square 72, the patient is asked to observe if anyof the segments of the grid are missing, wavy or otherwise distorted. Ifthey are, macular degeneration or other disorders may be present.Patients with macular degeneration are normally asked to do the Amslergrid test very regularly, often daily, and to report any changes intheir condition to their doctor. As macular degeneration is adegenerative disorder and certain possible conditions can lead rapidlyto blindness if not treated, it is critically important to monitor forchanges in a patient's condition.

In this preferred embodiment, the screening capability of a simple paperAmsler grid 71 is extended to provide a more complete measurement,tracking and training capability. Instead of a paper grid, the image ofFIG. 7 is a computer display of an Amsler grid 71 shown in the binocularviewer 110 b. Looking through the binocular viewer 110 b, the user 12 bcan be tested separately in each eye. The user 12 b can use a mouse,game controller 112 or other human input device to indicate where he orshe notices missing grid segments, wavy lines, or other distortions.This may be done easily by positioning a cursor on the Amsler grid 71over the affected area and detecting, but could also be done usingreference marks on the display and entering the location manually with akeyboard 15 or other human input device. By simply indicating whichregions of the display are affected, the user 12 b can quickly input arough indication of their condition. If each affected Amsler grid 71segment is indicated (again, either by detecting with a cursor, enteringreference numbers or codes, or some other method), a more preciseassessment of the condition of the user 12 b can be made. The test canbe quickly and easily repeated several times to ensure consistentresults. Variations in the test are also possible. For example, insteadof running the test with black lines on a white background as shown inFIG. 7, the scheme can be reversed so that a white grid appears on ablack background. A colored grid with either a black, white or coloredbackground can also be used. Variations in the size of the grid sectionsand the thickness of the grid lines 74 can be used. Color, brightness,contrast, grid size, grid line 74 thickness or any other possible aspectof the Amsler grid 71 can be varied to provide an enhanced test formacular degeneration or other retinal disorders in each eye. Using abinocular viewer 110 b, it is possible to not only test each eyeseparately, but also to show a combined image to the user 12 b so thatthe ability of the user 12 b to compensate for limited vision in one eyewith help from the other eye can be assessed. While this is most readilyachieved by simply asking the user 12 b to indicate any missing, wavy,or distorted segments in the Amsler grid when viewed with both eyes atthe same time and to then compare the results to the responses of theuser 12 b for each eye alone, more sophisticated diagnosis is alsopossible. One example is to present the Amsler grid 71 to both eyes andthen to drop some segments of the grid (or reduce their line width, makethem dimmer, etc.) from the view of one eye in an area of that eye thatis suspected to be affected by macular degeneration. The user is askedto note if any difference in his or her vision was noticed when the gridsegment was dropped or altered. If the user 12 b doesn't notice thechange, the same segment can then be dropped or altered from the view ofthe other eye, while maintaining the dropped or altered view for thefirst eye. When the grid segment is dropped or altered in the view ofthe second eye, the user 12 b should then notice it. In this way,retinal function can be mapped for both eyes while the user 12 b viewsthe Amsler grid 71 with both eyes. Such a test verifies thedisease-affected area by ensuring that the user 12 b does not noticecertain changes to the grid through the area of the eye affected bydisease. In this way, the Amsler grid 71 test is undertaken while theuser 12 b is seeing with both eyes in a very natural way.

FIG. 8 shows an image of a moving line test 81. Within display screenboundary 52, moving lines 82 appear, extend, contract and rotate slowlyon the display as the user 12 b observes them. The lines can be indifferent colors and thicknesses and the background color can be varied.The user 12 b looks into the center of the image and watches foranomalies such as dropped line sections, wavy lines and otherdistortions. When the user 12 b sees an anomaly, he or she detects thelocation with a cursor using a mouse, game controller 112, or otherhuman input device (or uses reference marks to indicate the location asdescribed above with reference to the Amsler grid of FIG. 7). It may bebeneficial to provide a reference image of some sort in the center ofthe display so that the user has a central reference point, similar tothe center square 72 of the Amsler grid 71 shown in FIG. 7. However, thecenter of rotation of the moving lines 82 may also serve this function.The moving line test 81 is not a standard test for retinal function. Itis presented here as an example of an additional test that can be run totest a user's vision for macular degeneration or other retinal disordersto ensure that results from the Amsler grid 71 are repeatable andconsistent. As with the Amsler grid 71, the moving line test 81 can bevaried in color, brightness, contrast, line weight, background color andother aspects.

FIG. 9 shows a display 91 with crosshairs 92. The crosshairs 92 arediagonal within the display screen boundary 52. Other types ofcrosshairs, such as common vertical and horizontal crosshairs such asthose used in rifle scopes, could also be used. The use of crosshairs 92or other visual reference marks is very important in video therapy forpatients with macular degeneration. Since macular degeneration resultsin a loss of central vision, it may not be possible for some patients toreference a single central point alone. Consequently, it is important toprovide a vision reference marking in the display that allows the user12 b to align their vision using primarily their peripheral vision.Crosshairs offer benefit for this alignment versus simple markings inthe display periphery as they are always visible adjacent to the centralvision of the user 12 b regardless of the degree of central vision thatthey have lost. That is, crosshairs always allow the user to make bestuse of whatever central or peripheral vision they have remaining whereasmarkings limited to the display periphery do not. Also, it should beexplained that it is not enough to only properly align the binocularviewer 110 b to the face of the user 12 b if areas of the video displayimage are to correspond to specific areas of the patient's retina.Clearly, the user may rotate their eyes left, right, up or down, so itis additionally important that the user 12 b look into the binocularviewer 110 b directly and at a correct and consistent angle. For thatreason, the user 12 b should be asked to look to the center of thecrosshairs 92. The moving line test 81 of FIG. 8, for example, wouldalso benefit from crosshairs to allow the user to fix their vision in arepeatable way for the test. As previously described, a significantadvantage of a head mounted binocular viewer 110 b such as the one shownin FIG. 2 is that since it mounts to the head of the user 12 b, it canbe mounted in an accurate and consistent fashion. If used correctly, andif the video measurement includes use of crosshairs or other visualalignment marks, the vision measurement and training system 11 is thencapable of concentrating on specific areas of the retina. Of course, itis beneficial that the system make some checks to ensure properalignment before the therapy is begun. Since some areas of the retinamay have been impacted by disease, it is possible to simply detect theseregions and compare them to the affected regions found in prior therapysessions. In this way, the vision measurement and training system 11 canensure that the therapy is applied correctly. It is also possible todetect a user's natural blind spot (all human eyes have a blind spot inthe retina where the optic nerve departs the eye) as an additionalreference to ensure that eye alignment is correct. Detecting the naturalblind spot has the added benefit that its location and size will notnormally change as a user's vision disorder changes as result ofprogress of the disease or effectiveness of a treatment. Detecting thenatural blind spot can be done by placing a feature in the display nearthe expected location of the blind spot and requesting that the user 12b to move it through interaction with a human input device until thefeature disappears. Other ways of detecting the natural blind spot arealso possible. Of course, eye tracking devices based on image processingof camera images such as through the video camera with lens 212 aspreviously described or other schemes to track the eyes of the user 12 bcan also be used. However, the added cost may not be justified. Sinceonly measurement and training are being applied to the eye, amisalignment only means that the measurement may be faulty or thetraining less effective, but no immediate harm is caused (as might be,for example, if eye misalignment occurred during a laser surgeryprocedure). Reasonable misalignment of the binocular viewer 110 b to theface of the user 12 b can be accommodated by shifting the therapeuticimage location on the display slightly. Large misalignments may resultin the vision measurement and training system 11 advising the user torealign the binocular viewer 110 b.

FIG. 10 shows a display 101 with crosshairs 92, display screen boundary52 and disease-affected region 102. A disease-affected region 102 is thearea of the display that corresponds to the disease-affected area of theretina of the user 12 b. It is noted that while the disease-affectedregion 102 is shown explicitly in FIGS. 10, 11, 12, 13 and 14, that inthe vision measurement and training games that will be discussed later,that the region would not normally be marked in the binocular viewer 110b so as to be visible by the user 12 b. That is, the disease-affectedregion 102 is explicitly marked in FIGS. 10, 11, 12, 13 and 14 tofacilitate understanding but is not normally so marked in the actualimage that a user 12 b sees when viewing the images. As described abovewith regard to the moving line test 81 and the Amsler grid 71, adisease-affected region 102 can be first assessed by direct user 12 bfeedback. Later, it will be explained how such a region can be moreprecisely mapped. The disease-affected region 102 is shown as a singlecontiguous region in FIG. 10, but it is possible for patients to havemultiple affected regions in their retina. In such cases, several suchdisease-affected regions 102 may be present. As the measurement andtraining regimens to follow are explained, it is important to note thatall of them can be effectively applied by either treating eachdisease-affected region 102 separately, or to cover them in a combinedfashion (for example, in a case where multiple small affected regionsare present). It is also clear from FIG. 10 that the use of crosshairs92, or other alignment schemes to direct the user 12 b to look into thecenter of the display are beneficial as some users 12 b have nosignificant central vision ability. In addition to substantial loss ofvision in the disease-affected region 102, a user 12 b is also likely tosuffer loss of vision clarity in the adjacent areas of the retina andpossibly across the entire scope of their vision. For that reason, it isimportant that all vision measurement and training include options for avariety of colors, line weights, levels of detail, brightness, contrastand other aspects so that the vision measurement and training system 11can be controlled (either manually or self-adapted through observationof the performance through of the user 12 b the measurement and/ortraining session) to fit specific needs.

FIG. 11 shows an image from a simple game that could be used in themeasurement of macular degeneration or other retinal disorders, inparticular, it shows a game involving incident and departing lines 111.As in FIG. 10, the display boundary 52, crosshairs 92 anddisease-affected region 102 are shown. In addition, an incident line 112and a departing line 114 are shown. In this game, the incident line 112appears first as only a point near the display boundary 52 and it beginsextending over time toward the disease-affected region 102. Once itenters the disease-affected region 102, a short time passes and then thedeparting line 114 appears first at the very edge of thedisease-affected region 102 and then extends over time toward thedisplay boundary. The departing line 114 could also begin in other areasof the display so that a complete measure of vision field could begenerated. In this simple game, the user 12 b simply indicates whichsection of the display as defined by the crosshairs 92 the departingline 114 appears in. As shown in FIG. 11, the departing line 114 appearsin the upper section of the display, so the user 12 b would indicatethis using a keyboard, mouse, game controller 112 or other human inputdevice. The sooner the user 12 b can correctly indicate the section ofthe display the departing line 114 appears in, the higher the user'sscore. Clearly, the speed of the incident and departing lines, theircolor, weight, contrast, the background color, and other aspects of thegame can easily be adjusted to account for the specific capability ofthe user 12 b. And clearly, the time taken by the user to recognize thedeparting line 114 is an indication of his or her ability to recognizethe line and, hence, is an indication that can be used to refineknowledge of the disease-affected region 102.

Since macular degeneration and some other disorders occur primarily inolder patients, user 12 b reaction time and physical dexterity arefactors in game play. For the game involving incident and departinglines 111 shown in FIG. 11, very simple feedback based on what sectionof the display the departing line 114 appeared in was used, so thatusers 12 b with limited dexterity might still play the game. Asdiscussed before with regard to FIG. 5, reaction time can be assessed byobserving the performance of the user 12 b under special conditions (inthis case for example, for very slow moving incident and departinglines) and can then be subtracted from other results to determine ascore that is reflective mainly of vision acuity and only minimally tophysical reaction time.

Once the reaction time of the user 12 b and his basic ability to playthe game has been assessed, the vision measurement and training system11 can use the game involving incident and departing lines 111 to moreprecisely map each disease-affected region 102. Each time the usersignals a departing line, the system can use the knowledge of when andwhere the departing line 114 was started on the display, when the user12 b signaled it and whether the user 12 b correctly signaled whichsection of the display it appeared in to fine tune the assessment of thelocation and extent of each disease-affected region 102. With ongoinggame play, the location and extent of each disease-affected region 102can be more precisely mapped. Of course, some regions of the retina willhave more function than others, so it is also possible to grade thevision of the user 12 b based on his or her game-play ability. That is,instead of only indicating a disease-affected region 102, regions thatare very badly affected might be indicated separately from regions thatare only moderately or minimally affected by the disease (clearly, verymany possible ways to grade vision condition as a function of locationin the retina with varying degrees of complexity and benefit arepossible) This information could then be used to enhance the overallsystem effectiveness. If the training were, for example, the gameinvolving incident and departing lines 111, as shown in FIG. 11, gameplay might be concentrated in specific regions with line colors,weights, game speed and other factors adjusted to enhance the benefit ofthe training for the condition of the user 12 b for that specific regionof the retina.

FIG. 11 also includes a flash 116 of light in the disease-affectedregion 102 near the location of the departing line 114. In the gameinvolving incident and departing lines 111, this flash 116 is anoptional hint to the user 12 b that attempts to train the vision of theuser 12 b. If the user 12 b can see the flash, he or she can increasetheir score by indicating the display section of the departing line 114possibly even before the line appears. In this way, the user 12 b valuesthe ability to observe the flash 116 and will concentrate to use andhence train, what remaining vision ability they have in thedisease-affected region 102. Clearly, the color, intensity, contrast,size, location, duration, timing or other aspects of the flash 116 canbe varied to provide beneficial effect to the user 12 b. And asdiscussed above, if the condition of the retina is graded to indicateregions of the display that correspond to badly, moderately, orminimally affected areas (or other possible grades of visionperformance), the flash 116 can be adapted for use in each such region.Of course, many different hints could be provided to the user 12 b withsimilar effect to the flash 116 described here. In fact, it is alsopossible to provide audible hints, vibration, or other stimulus to theuser 12 b to draw his or her attention to some feature of the game toimprove concentration on some object and increase the benefit of thetraining. For example, the audio stimulation of a popping sound as thedeparting line 114 is started might increase the attention of the user12 b to the game.

As noted above, the user 12 b could have multiple disease-affectedregions 102. In such a case, the game involving incident and departinglines 111 is simply extended to include all such regions. It is alsonoted that for the user 12 b, to observe the flash 116, if it is used,it may be beneficial if the pupils of the user 12 b are dilated to allowthe most possible light to enter the eye. To create this situation, thegame involving incident and departing lines 111, may be adjusted so thatthe background is either black or very dark and the finest possiblelines and minimum amount of light is used in the display image that issuitable for the condition of the user 12 b. This will cause the pupilsof the user 12 b to dilate and give the user 12 b the best chance ofseeing the flash 116. The concept of using a mainly dark display so thatthe pupils dilate is an important concept.

Another aspect of vision training for macular degeneration is parafoveatraining. That is, training the user 12 b to make best use of the areasof the retina that are not substantially affected by the disease. Thefovea is the central retina, so parafovea training is training the user12 b to use his or her peripheral vision to accomplish tasks that wouldnormally rely mainly on the central retina. As will be discussed laterwith regard to FIG. 14, parafovea training is best accomplished with 3Dimages and stereoscopic vision, but some benefit can be achieved withsimpler games such as the game involving incident and departing lines111. In this game as described, the user already watches the incidentline 112 and departing line 114 as they move through the sections of thedisplay that do not correspond to the disease-affected region 102. Ifthe game is extended so that the point where the departing line 114exits the display provides a hint for where the next incident line 112will appear, the user 12 b is then benefited by closely observing wherethe departing line 114 exits the display (for example, the next incidentline 112 might first appear diametrically opposed to where the lastdeparting line 114 exited, but many other schemes are clearly possible)In this way, the user 12 b is benefited to make use of their peripheralvision and parafovea training is achieved. Clearly, much moresophisticated enhancements are possible. Enhancements to a game toextend the interest of the user 12 b to the peripheral areas of thedisplay may be quite desirable.

It is also noted that vision training for patients with retinaldisorders that do not go to the lengths described above to ensure goodalignment of the video display to the patient's retina and may also notattempt to assess what parts of the retina are affected by maculardegeneration are possible. However, there are many millions of photoreceptors in the retina, so there is a large benefit to attempt toconcentrate training where the most benefit may be received. And forsome patients, games that fail to first assess the patients visionability could result in simply displaying games that are impossible forthe patient to play with any measure of success. One strategy for such asituation, that may also be useful for very extreme cases of maculardegeneration or for patients with very poor motor skills or dexterity isto play a game that varies the game play from location to location onthe display so that the patient can engage and play the game for atleast a part of the therapy session.

FIG. 12 shows a display image of a game based on circular tennis 121. Inthe game, a moving tennis ball 128 is deflected from a disease-affectedregion 102 and a flat section 122 of a circle 1210. The user 12 b needonly rotate the circle 1210 so that the flat section 122 contacts thetennis ball 128. This operation is simply accomplished through manydifferent possible human input devices. Note that the circle 1210 in thegame based on circular tennis 121 provides a reference for the user 12 bto align their eye to the display in addition to the crosshairs 92. Theincident trajectory 124 and reflected trajectory 126 may be responsiveto the point where the tennis ball 128 strikes the flat section 122 anda disease-affected region 102. In such a case, the game play could bemore varied and interesting. Clearly, if a patient has multipledisease-affected regions 102, the game based on circular tennis 121might encompass all of them inside the circle 1210 and treat themtogether, or otherwise treat them separately and play around each ofthem in sequence. It is clear that in the game based on circular tennis,the ability of the user 12 b to play a specific situation of thereflected tennis ball 128 allows knowledge of the disease-affectedregion 102 to be improved. It is noted incidentally that FIG. 12 alsoshows crosshairs 92 and display screen boundary 52.

FIG. 13 shows a display image of a game based on shooting enemy objects131. In this game, enemy objects 134 emanate from a disease-affectedregion 102 along various departing trajectories 132. The user 12 bcontrols the horizontal position of a gun 138 and shoots at the enemyobjects 134 to create explosions 136 that destroy them. The more enemyobjects that are destroyed, and the closer they are destroyed to adisease-affected region 102, the higher the score. And clearly, theability of the user 12 b to play can be used to enhance knowledge of thedisease-affected region 102. Here, if multiple disease-affected regions102 are presented, enemy objects 134 might simply deploy from all ofthem, or they could be treated in sequence and other possibilities alsoexist. It is noted incidentally that FIG. 13 also shows crosshairs 92and display screen boundary 52.

In FIG. 11, 12 and 13, simple games were illustrated that showed how auser's interest could be drawn to increase use and concentration oncertain areas of the retina and how game plan ability can be used ameasurement capability to assess vision performance and refine knowledgeof the disease-affected region 102. In each case, a very wide variety ofcolor schemes, contrast, brightness, feature size, game speed and othercharacteristics were possible to accommodate a given user's needs andability to play an interactive game. Each game can attempt variouscolors, line widths, contrast and all other parameters and monitor theuser's progress to determine the limitations and capability of thevision of the user 12 b. It is also possible for each game to be playedseparately for each eye or to combine play so that while both eyes viewmuch of the same image, that one eye only will see some importantaspects that allow the vision measurement and training system 11 tomeasure and train each eye separately or together. That is, some specialfeatures in the image are presented to only one of the eyes of the user12 b and those features are simply not displayed on the side of thebinocular viewer 110 b for the other eye. Additionally, games could bedevised using 3D stereoscopic vision images so that items only intendedfor one eye to see could be situated in the 3D image so that only oneeye would normally see them as was described with regard to FIG. 6.Clearly, a very wide variety of games are possible.

FIG. 14 shows a representation of a game with three dimensional object141. The display boundary 52, crosshairs 92 and disease-affected region102 are all visible. The three dimensional object 142 is a box thatsurrounds the disease-affected region 102. The game with threedimensional object 141 is presumed to be played in stereoscopic visionso that the user 12 b sees a very real three dimensional object 142 thathas true perspective and parallax. In one possible embodiment of thegame with three dimensional object 141, the three dimensional object 142rotates and the user 12 b plays the game by interacting with images onthe faces of the object. One possible such image is the target 144 shownon the right face of the three dimensional object 142 in FIG. 14. Aseach face rotates into view, the user 12 b first sees the target 144 inhis or her peripheral vision. In this way, the vision acuity of one ofthe eyes of the user 12 b can be assessed separately and the trainingroutine is directed to the peripheral area. Depending on whether thethree dimensional object 142 rotates to the left or right, one eye orthe other will see each face first. The use of such a game with threedimensional object 141 is helpful for patients who have lost some visionfunction (such as the disease-affected region 102) and need to learn touse their peripheral vision more extensively to perform every day tasks.This is very difficult for many patients as their neural functions havealways depended on central vision through the course of most of theirlives. It is also very clear that using three-dimensional stereoscopicvision images through a binocular viewer 110 b is dramaticallyadvantageous since the user 12 b needs to view images that are veryclose to those from natural vision in the real world. As the capabilityfor adaptive focal depth explained with regard to FIG. 3A and FIG. 4 isa further ability to help the user 12 b feel they are in the real world,inclusion of adaptive focal depth into the game with three dimensionalobject 141 is also a clear advantage. Training a user 12 b to use theirremaining peripheral vision function is sometimes referred to asparafovea training.

Parafovea training with a binocular viewer 110 b with adaptive focaldepth capability also has other benefits. The ability to produce morenatural images should result in better comfort for some users 12 b.Indeed, using only one eye for extended periods, as might be attemptedwith other approaches to computerized parafovea training, may result inuser 12 b discomfort and introduces the complication of binocularfunction, convergence and fusion not being a specific part of thetraining session. Lack of binocular images would leave the key abilityto combine (fuse) images together from each eye to create a true senseof space apart from the training. Hence, user 12 b comfort and theability to provide real binocular training are substantial benefits touse of a binocular viewer 110 b with adaptive focal depth.

As with the other game examples, the game with three dimensional object141 can be altered to use different sized objects, different rotationspeeds, different colors, different contrast, different brightness andother variations. Clearly, a similar concept can also be applied to manyother possible gaming environments. For example, instead of viewing arotating box, the game could comprise a view from the cockpit of anairplane that is flying through an interesting region (such as a canyonor city central region). As the airplane travels through the region,images come into view first in the peripheral region of one eye or theother as the plane turns and rotates. Hence, the use of any game playthat causes sequences in a 3D stereoscopic vision display to preferablydemand the use of peripheral vision and where this effect is used toassess vision acuity and/or to provide training, is a part of thispatent application. Clearly, the concept described can be applied tocars traveling on a road (or off road), a person running through thejungle (or anywhere) and perhaps an infinite number of environments andsituations. One common environment that is used already in gaming thatcould be easily adapted to the video game environment described here arethe so-called “first-person shooter” games. In these games, the user iseffectively behind a gun and is going through an interesting environmenthunting for enemies. Normally, there are many turns and twists so thatthe three dimensional environment would have many areas that would comeinto first view in the peripheral vision region if a real stereoscopicvision display is used, such as the binocular viewer 110 b shown in FIG.2.

FIG. 15 shows a graphical representation of a vision field database 151for one or both of a user's eyes. How misalignment of the binocularviewer 110 b can be detected and corrected will be described. It will beassumed initially that eye tracking using the camera with lens 212 inFIG. 2 is not activated. Severe vision loss data region 152 correspondsto an area of the vision field of the user 12 b in which vision wasmeasured to be severely impaired or nonexistent. Moderate vision dataregion 153 corresponds to an area of the vision field of the user 12 bin which vision loss was measured, but some vision function remains. Andnormal vision data region 156 corresponds to an area of the vision fieldof the user 12 b in which normal or nearly normal vision function wasmeasured. Note that the vision field test limit 1512 is not the same asthe display screen boundary 52 shown in some prior figures. The reasonis that the user 12 b can be directed to look toward one of the screenboundaries as his or her vision field test is extended in the oppositedirection. For example, if the user 12 b is directed (normally with avisible stimulus such as a target or other object) to look toward thefar right, his or her peripheral vision toward the left can then bemeasured further than it could if the user 12 b simply looked straightforward. And this technique can be repeated in every direction. Hence,the vision field test limit 1512 can substantially exceed the displayscreen boundary 52. Clearly, many possible vision scoring schemes andmany levels of gradation of vision function are possible versus thesimple three regions (normal, moderate vision and severe vision loss)demonstrated here. One simple measure is simply to record the number ofcorrect versus incorrect user 12 b responses in a given region of visionfield using one of the tests explained earlier, such as the gameinvolving incident and departing lines 111 in FIG. 11. In this way, theareas of vision function would be a simple percentage and could then beorganized into specific gradations of vision function or could even bestored in the database as a continuum of values. The blind spot dataregion 158 is the representation of the natural blind spot(corresponding to the place where the optic nerve departs the eye) ofthe user 12 b. It is important to note that the normal vision dataregion 156, the moderate vision data region 153, the severe vision lossdata region 152, and the blind spot data region 158 are representationsof stored data in a database that might be from a single test taken onthe user 12 b at a prior date or time, or could perhaps be compositedata that has been derived from the combination of multiple prior tests.That is, the data regions shown in FIG. 15 might be single test resultsor averages, weighted averages, or other combinations of past data frommultiple tests or tests taken at multiple times.

The severe vision loss new measurement region 154, the moderate visionnew measurement region 155, and the blind spot new measurement region1510 all correspond to new measurement data collected in an ongoing orpast measurement session that are to be combined with the existing data.It is very clear in FIG. 15 that while the overall shapes and sizes ofthe vision loss new measurements correspond to those from the data inthe database, that they are misaligned. This is also clear from thelocation of the blind spot new measurement region 1510 versus the blindspot data region 158. If the new measurement is ongoing, it is possibleto alert the user 12 b through the vision measurement and trainingsystem 11 that a misalignment exists and that the binocular viewer 110 bshould be adjusted. Of course, even with careful adjustment, the user 12b will only be able to achieve an approximately correct alignment of theviewer to his or her face. Consequently, it is also important that smallmisalignments be corrected automatically through scaling, shifting,rotation or other possible transformation of the data recordscorresponding to the measurements. In the example of FIG. 15, the newdata horizontal axis 156 a and new data vertical axis 156 b provide somereference for the amount that the new data should be rotated (as shownit would be clockwise) before being shifted to correspond to thealignment of the existing data. Of course, the new measurement data willnot normally correspond perfectly to the existing data since the visionof the user 12 b may well have changed since the existing data wastaken. Consequently, the new measurement data should be rotated, scaledand/or shifted (these operations might take place in any order) and thencorrelated with the existing data to achieve the best overallcorrelation before being combined with the existing data.

Of course, a single measurement session for vision field can involvemany thousands of data points, so it can be frustrating if the user 12 bis asked to realign the binocular viewer 110 b and rerun the test due tomisalignment. Consequently, it is beneficial to organize the test gamesso that basic alignment data can be collected in the first few minutesof game play. That is, some key alignment measures relating to the blindspot of the user 12 b and vision loss regions can be collected quicklyto provide an adequate indication that the binocular viewer 110 b issufficiently accurately aligned that the test can go on and anyremaining misalignment can be corrected by shifting, rotating andscaling the data as described above. This concept can be extended toinclude occasionally revisiting the issue of viewer alignment in thecourse of the game to take some basic measurements and ensure the vieweralignment has not shifted. In the event the viewer alignment hasshifted, the measurement data can be rejected and the user 12 b advisedto restart the test and to be more careful about alignment.

The concepts regarding alignment as explained above with regard to FIG.15 can easily be extended to include the situation in which eye trackingmeasurements are taken using the camera with lens 212 shown in FIG. 2.In the case that eye tracking is used, the vision measurement andtraining system 11 will have accurate data regarding the direction eachof the eyes of the user 12 b are looking when each measurement is taken.Consequently, the user 12 b only needs to be alerted if the binocularviewer 110 b has been poorly aligned when the test begins and the eyetracking capability alone is normally adequate to do this (that is, nospecific testing need take place as the eye tracking capability willdirectly report eye alignment). And, each measurement data point can beeither corrected for misalignment or discarded if eye alignment wassufficiently poor that the measurement is of suspect quality.Regrettably, eye tracking systems can be rather expensive and are notnormally included in commercially available binocular viewers, hence,the techniques outlined above to deal with eye alignment are beneficialfor development of low-cost systems. It is also possible to combine thealignment detection and correction techniques described above with theuse of eye tracking. This might be especially important if the user 12 bmoves his eyes so quickly that the eye tracking system is unable toreact and the movement, while unnoticed by the eye tracking system,results in erroneous data.

As previously noted, many vision disorders need to be carefullymonitored and tracked as a worsening condition can quickly lead toblindness if not treated. In the case of macular degeneration, forexample, wet macular degeneration in which actual bleeding of the retinaoccurs may develop and should be treated very quickly. If such asituation arises, the vision measurement and training system 11 wouldanalyze the existing data regions of FIG. 15 and find that theycorrelate below an acceptable threshold with the new measurementregions. The level of acceptable correlation can be set by a careprovider and may depend on many factors including the condition, age andpast treatment history of the user 12 b. The level of acceptablecorrelation may also be adapted to the length of time that is spannedfrom the time the existing data regions where updated to the time thatthe new measurement data was collected. In any case, if the newmeasurement data and existing data for the user 12 b fail to correlatewith each other to an acceptable level, the user 12 b can be alerted bythe vision measurement and training system 11 to seek help from aprofessional care provider.

The vision measurement and training system shown in FIG. 1 is clearlycapable to build a rather sophisticated database of the visioncapability of the user 12 b for each of the eyes of the user 12 b.Additionally, the database may include information entered by a doctoror care provider based on their diagnosis of the user 12 b, informationinput by the user 12 b regarding their condition and from the results ofthe basic tests such as the Amsler grid 71 test and also frominformation gained by the performance of the user 12 b in game play forgames such as the game involving incident and departing lines 111.Information in this database can be reported to a doctor or careprovider and can be formatted to be highly useful for them. The databaseinformation can also be used to adapt training or measurement by thevision measurement and training system 11 automatically. Clearly, insuch a database, it may be beneficial to give different weight tocertain information depending on how it was received. For example,specific information from an eye doctor may be considered absolute andto be trusted regardless of other information the vision measurement andtraining system 11 may determine. Information received from user 12 binput such as the Amsler grid 71 test may be treated with some suspicionunless it is reasonably consistent with information from the eye doctoror other sources. And information received from the results of game playmight only be trusted once verified to be consistent with otherinformation sources. Clearly, through a reasonable system that includesinformation regarding confidence factors related to all informationreceived, it is possible to build a vision measurement and trainingsystem 11 that provides benefit to a user 12 b without being responsiveto misguided, incorrect, or even possibly malicious information it mayreceive. However, since the system is providing only measurement andtraining, there is little risk of damage to the user 12 b. And, ifinformation from multiple sources is not sufficiently consistent toallow the system to confidently provide useful results, the visionmeasurement and training system 11 may alert the user 12 b to thiscondition with directions that the user's eye doctor be consulted.

It is also clear that the video images and displays shown herein alloffer the possibility for a multitude of colors, brightness, contrast,line weights, game speed and other adjustments to the specific conditionof the user 12 b. With such a wide variety of adjustments, it ispossible for adjustment of the system to become burdensome, especiallyfor a doctor who is beginning a new user 12 b, for example, on thevision measurement and training system 11. However, with a reasonablebeginning point, it is possible for the system to self-adapt all thesesettings based on the responses and game play results of the user 12 b.Some very simple initial settings may be included in the visionmeasurement and training system 11 to simplify this situation. Forexample, the level of macular degeneration or other disorder might beinput simply as minimal, moderate, or severe and the ability of the user12 b to play with good dexterity might be characterized as simply poor,fair, or good. In this way, basic information is provided to the visionmeasurement and training system 11 with which it can adapt suitably forthe user 12 b.

While specific measurement games would normally be used for visionmeasurement, vision training can possibly also make use of images thatare commonly used in every day life so that the user 12 b can takebenefit from vision training in the course of their normal every dayactivity. In FIG. 16, a flow chart is shown that outlines some of thesteps needed to create images suitable for vision training usingcomputer images used with common computer applications 161. The exampleof FIG. 16 is for a vision training regimen concentrating on focusingability, but it is clear that many possible regimens could be devised ina similar fashion. These common applications include spreadsheets, wordprocessors, internet browsers, photograph editing tools and othercomputer applications. The process begins with the original computerapplication software 162. First, a software process to create a 3Dversion of the software 164 is applied to the computer applicationsoftware 162 to create a 3D version of the display images the computerapplication software 162 produces. The result is a 3D display version ofthe computer application software 166. Since most computer applicationsare 2D (two dimensional), this might involve taking some assumptionsabout the distance of various objects in the display image, or mightonly involve creating the correct parallax and focal depth so that theimage would appear in 2D at a focal depth that could be varied over time(note that even though the image would appear 2D in this case that thebinocular viewer 110 b could still be used). The resulting softwarewould then be subjected to a software process to vary distance andlocation of images in the software application 168, resulting in aversion of the computer applications software including vision trainingcapability 1610. Finally, a software process to control user specificcharacteristics 1612 such as color, line width, preferred focal depthand other aspects is applied to create a version of computer applicationsoftware ready to be displayed 1614. The software process to control theuser specific characteristics 1612 may also involve using software tovary the parallax and focal depth of various objects in the image if afull 3D image is created or to simply vary the parallax and focal depthof the full image at once if a 2D image is to be created. As an example,consider a computer user desiring vision training at various focaldepths viewing a document in a common word processing application. Theprocess of FIG. 16 could create a 2D version of this applicationsuitable for display on binocular viewer 110 b, it would then generatethe parallax and focal depth information needed by binocular viewer 110b to generate the 2D image at varying distances. Finally, it wouldgenerate a sequence of distances that the resulting 2D image would beviewed at to create a vision training routine. The length of time theimage stayed at a given distance, whether it changed gradually fromcloser to further away or moved suddenly, lateral or vertical movementof the image over time and other aspects of the image could all becontrolled. Since the user would normally have access to a humaninterface device such as a keyboard, mouse, or other interface whenusing a computer application, the vision training could also beresponsive to the user's wishes to speed up, slow down, stop orotherwise alter the routine. For example, a user 12 b reading a documentover the internet might want each page to appear at a differentdistance, but might not want the system to vary the distance in thecourse of his or her reading each page. Another example could be a user12 b viewing technical drawings that might desire the routine to stopbriefly on command so that specific features could be studied in detailwithout distraction.

The vision training system using computer images used with commoncomputer applications 161 shown in FIG. 16 is illustrated as a series ofdiscrete processes for illustrative purposes. In most embodiments, it islikely that continual or otherwise different data processing strategywould be applied in which images from the original computer applicationsoftware 162 would be intercepted before being sent to the computerdisplay 16 and would be altered as needed to create the necessarydisplay and control information for the binocular viewer 110 b. Ofcourse, there are many (perhaps infinite) possible variations for howthis processing could be undertaken without deviating from the scope ofthis patent application.

It is also clear that the discussion above on the vision training systemusing computer images used with common computer applications 161 can beextended to include video images generated by other means than computerapplications. For example, television images could also be transformedin a very similar way and could also be incorporated into a visiontraining system. Video from television, video tapes, DVDs, camcorders,digitally recorded video, compressed video, still images, mobiletelevision, internet TV and other sources could all be used in a similarfashion and their use as video source material that can be manipulatedto create eye exercise therapy materials is considered a part of theinvention. This will be explained further later and is illustrated forthe specific case of television signals in FIG. 17.

It is also noted that if a camera system were included in the visionmeasurement and training system 11, the captured images could besubjected to the process of FIG. 16 or a similar process so that theycould also be used as part of a vision training routine. An example ofthis would be a person reading a text book. As each page is flipped, thecamera could capture the image and the vision measurement and trainingsystem 11 could provide an appropriate version of it for trainingpurposes.

FIG. 17 shows a possible embodiment of another system that could providebenefit to persons with vision disorders. In FIG. 17, an enhancedtelevision system 171 is shown, in which a television 172 is connectedto a control box 176 through an electrical cable to control box 174. Thecontrol box 176 is connected to binocular viewer 110 a through anelectrical cable 178. The television 172 in FIG. 17 is shown mainly forillustrative purposes since, as long as the television signal or someother commonly available video signal is available in some fashion thepresence of an actual television 172 is optional. In the enhancedtelevision system 171, the control box 176 operates on the television orother video signal to create beneficial images. Note that the controlbox could be programmable so that information it receives from a careprovider, the vision measurement and training system 11, or othersources could be used to adapt the creation of images in the control box176 to optimize the video a given user 12 d receives. The enhancedtelevision system 171 shown in FIG. 17 may be especially beneficial tousers who are unable to operate a computer system, unable to operate agame controller (for example, patients with poor coordination, arthritisor other conditions affecting their physical ability) or who normallywatch television or other video for many hours each day.

The enhanced television system 171 is capable to create a wide varietyof images. For example, a user 12 d with macular degeneration maybenefit from an image that is distorted so that some of the image thatwould normally fall into the center of the display is stretched so thatmore of the interesting detail falls into the periphery of their vision(parafovea). In addition to allowing the user 12 d to better view theimage or video, this technique may also be beneficial as parafoveatraining. If the control box 176 is provided information about aspecific condition of the user 12 d, this stretching of the image couldbe adaptive to their specific needs. Other alteration of the incomingvideo signal is also possible. Simply making the image in thedisease-affected region 102 brighter, higher contrast, or altering thecomposition of colors in it might be helpful for users 12 d with onlymild macular degeneration. Use of edge enhancing video filters to createbolder edges and to eliminate fine details that create a confusing imagecould be applied. Detecting motion in the video stream, as is often donein video compression technology and using that information to crop thesignal and dedicate more of the display to the changing and moreinteresting part of the video image sequence could be beneficial. Andcertainly, a combination of cropping, stretching, enhancing, orotherwise altering a video signal to make it most useful and therapeuticto a user 12 d is possible.

Of course, the enhanced television system 171 of FIG. 17 can beimplemented in many possible ways. The control box 176 could beintegrated into the television 172 or the binocular viewer 110 a. It isalso possible that the complete system could be integrated into thebinocular viewer 110 a. And, of course, while the binocular viewer 110 aprovides key benefits as already described herein many times, it ispossible to use some of the techniques described with other displaytechnologies. Many other configurations including the use of imagesource files, television and other video and image files and signals ofall possible formats are considered part of this patent application.Also, it is clear that the control box 176 could receive visionmeasurement data from the vision measurement and training system 11 orfrom other source through a very wide variety of methods includingcomputer disks, tapes, data cards, internet file transmission, wirelesstransmission, wired transmission, or many other methods.

It is also noted that the vision measurement and training system 11described herein can be combined with other forms of eye therapy. Forexample, massaging the eyes before or after using the system might bebeneficial. It is also possible that drugs could be used to relax theeyes, stimulate or otherwise condition the retina or macula, orotherwise put the eye into a condition that makes vision training moreeffective. Hot or cold treatments combined with vision training and orthe use of physical exercise (e.g., running, stationary bicycle, etc.)by the user before, after, or during the eye exercise therapy may alsobenefit the therapy and produce better or more rapid results. And ofcourse, even other techniques such as acoustic, electrical, chemical, orother stimulation of the eye, or possibly the optic nerve might also befound beneficial in conjunction with the vision training techniquesdescribed herein. It is noted also that use of a head mounted displaysuch as the binocular viewer 110 b shown in FIG. 2, or another type ofdisplay that contacts the users 12 b face, could allow for the displayto include elements of a combined therapy. A strobe to provide brightflashes of light, a source for ultrasound, vibration, or audible soundto massage the eye, a heater, vibrator, fan, water jet, or otherfunction could be incorporated into such a viewer to augment thetraining regimens presented herein.

An additional possible combined therapy is the exercise of the musclesthat control the direction and rotation of the eye. There are severalmuscles around the eye that allow the eye to look left, right, up, down,etc. Normally, most of the techniques and therapies described hereinwill be done with the patient looking forward and maintaining alignmentof their eye to crosshairs 92 or other visual reference marks. However,vision training to treat strabismus, diplopia and some other disordersinvolves training of the muscles that control the direction of theeyeball. Hence, causing a user 12 b, to look sharply to the left, right,up, down, etc. (could also be at angles) or to roll their eyes in theireye sockets may be beneficial for some vision training. Tension from theeye steering muscles might also be beneficial in some therapies. Forexample tension from the eye muscles (especially tension from them whenthe eye is turned in the socket so that the tension tends to pulloutwardly on the side of the eye) might allow the eye to resume a morenatural shape instead of the elongated shape that is typicallyassociated with myopia. It is noted that some forms of vision yoga arebased on looking in certain directions and then returning to normalvision. Providing such a therapy is possible by simply moving theobjects of interest on the display to the far display periphery andpossibly removing the crosshairs or other vision reference marks fromthe display (and possibly alerting the user 12 b in other ways as well,such as telling them using a sound system or writing it on the display).In cases where the physical construction of the binocular viewer 110 bmay not provide a sufficiently wide field of view to cause the user tolook as sharply in a direction as desired, the user 12 b might be simplydirected (through audible, visual, or other methods) to perform theexercise (for example, “turn your eyes as sharply to the right as youcan”). It is also possible to add features inside the binocular viewer110 b housing that could assist the user 12 b to perform such a regimen.For example, a small light on the right side of the viewer such aslights 28 or 214 might come on when the user 12 b is asked to look tothe right to give the user 12 b a reference to look at (and similarlights could be included for up, down, left, right, lower right, upperleft, etc.) As noted previously, some commercial binocular viewers onthe market today incorporate position sensing ability. If suchcapability is available, it provides another method to ensure that theuser 12 b is really rolling their eyes in the eye sockets and not simplyturning their head in response to a command. And finally, some eyedisorders specifically associated with the eye steering muscles, such asvision convergence problems, may benefit substantially from a trainingregimen as described that causes the user 12 b to direct or roll theireyes in a certain way. And it should be clear, that with the binocularviewer 110 b and the methods for measuring vision and adapting trainingto the condition of the user 12 b that have been described herein, it isalso possible to assess problems with the eye steering muscles, assessprogress and adapt training so that the user 12 b receives the mostbeneficial therapy possible for eye steering muscle related conditions.

Since the vision measurement and training system 11 providesmeasurements that may be used for medical diagnostic purposes, it isessential that the system be properly interconnected from elements thatwere intended for each purpose. This is especially critical for low costsystems that might be constructed with “off-the-shelf” components. Sincecommon computer components are generally designed to interoperate aseasily as possible, it is possible for improper systems to beconstructed unless action is taken to ensure system integrity. Forexample, the binocular viewer 110 a might be incorrectly replaced withanother viewer offering lower screen resolution, that might result inpoor system accuracy. In FIG. 18, a high integrity vision measurementand training system 181 is shown. Central processor 182 is connected tothe other system elements through a logical interconnection 1814.Central processor 182 might be a computer, cell phone, PDA, gameplatform, or other central processing function. Logical interconnection1814 might be a wired connection such as USB (Universal Serial Bus), ora wireless connection such as Bluetooth. In fact, logicalinterconnection 1814 might be made up of several different physicalinterconnects. That is, logical interconnection 1814 could be commononly at a logical level and the physical interconnections to the varioussystem blocks could be over different physical interconnections. Othersystem elements are also shown. Box 1812 may represent a binocularviewer, while box 188 may be a human input device. Other displays,sensor, controllers, input devices, stimulus devices may also beconnected. For example, earphones 116 are shown in FIG. 1 and while notshown in FIG. 18, they could be added. Central processor 182 as shownincludes a secure memory 184 and encryption interface 186. The highintegrity vision measurement and training system 181 ensures systemintegrity by passing secure coded messages from the various systemelements to the central processor 182 to ensure that the system iscomposed of the proper devices with all the correct and necessarysoftware and hardware. While the system could be composed in a widevariety of ways, the preferred embodiment is for the central processor182 to send a secure encrypted request to box 1812 requesting that itidentify itself. Box 1812 then sends a response indicating its overallmakeup and configuration. The response from box 1812 would normally alsobe encrypted to ensure that someone trying to clone the system could noteasily extract the messaging scheme and generate a cloned system thatmay not meet the original system performance. The secure messagingbetween central processor 182 and the other elements (boxes) in thesystem might make use of a public key encryption system so thatdifferent encryption codes could be used for each operation of thesystem. Other secure encryptions are also possible and will not beenumerated here. Secure memory 184 would be used by central processor182 to ensure that the specific system requirements and security codesremain intact and are not available to hackers or others with maliciousintent. Encryption interface 186 would handle all encryption anddecryption including passing public keys to each box (element) of thesystem.

Of course, many other ways to ensure that the system is properlycomposed of the right elements and properly configured also exist. Onesimple method is to use proprietary hardware interfaces between thesystem elements or to use conventional interfaces with proprietaryconnector plugs that will not interoperate with conventional plugs.However, these approaches make it difficult to interconnectoff-the-shelf hardware that is readily available and perfectly adequatefor use in the system. For example, it may be desirable to design thevision measurement and training system 11 so that it can work with manydifferent human input devices to accommodate users 12 b with physicalhandicaps or conditions that make it hard for them to operate certaindevices. In this case, it is a great benefit to use conventionalinterfaces such as USB and ensure proper system operation and securitythrough the public key security system explained above or other possiblesecurity systems. And, of course, some elements of the high integrityvision training and measurement system 181 may not need to be checkedthrough a security protocol as described above if they are trulygeneric. It is possible that headphones, microphones and some otherpossible elements are sufficiently generic that available off-the-shelfcomponents can be used interchangeably in the system without risk ofunacceptable system operation.

With the security features of the high integrity vision measurement andtraining system 181 in place, additional benefits from system securitycan also be derived. For example, the user's information can beprotected to ensure that privacy is respected and only those withspecific permission can access databases and other information the user12 b may consider to be private. In the case of transmission of thedatabase information to a care provider's office, for example, thepublic key encryption system could be used to ensure that the databaseis received intact and was not intercepted or maliciously corrupted. Useof PIN (Personal Identity Number) codes, passwords, firewalls and othersecurity techniques to protect user 12 b information and privacy are allpossible.

From the description above, some possible advantages of certainembodiments of the invention are clear:

a) an automated computer system can be developed to measure and train aperson's vision;

b) binocular viewer technology can be applied to create images that varyfocal depth and parallax so that realistic images can be generated;

c) features and use of color can be applied to draw a user's attentionto a primary image and away from images in a practical display systemthat cannot have the correct focal depth or parallax;

d) images can be created that are beneficial for measuring and traininga users vision;

e) images can be created that allow a user to view a single stereoscopicvision image while objects of interest are included that allow vision ineach eye to be assessed independently;

f) data collected through an automated vision measurement and trainingsystem can be used to control other video systems to benefit a user;

g) security techniques can be applied to the system to ensure that it iscomposed of the correct elements and that each element is properlyconnected;

h) collected data can be added to a data base and the user can bealerted if changes in their vision warrant the attention of a healthcareprofessional; and

i) data from multiple games can be combined into a database so that theuser may use different games at different times so that the visionmeasurement and training remains exciting, interesting and engaging.

The benefits of the invention should be clear. It offers a system tomeasure and train a user's vision. The system can be implemented with avariety of display technologies, while the use of a binocular viewerwill provide very realistic images. The position and focal depth ofobjects in the display can be varied to create images very similar to areal world experience. In this way, the eye can be forced to focus as itwould when objects at varying distances are viewed in the real world.Data for many vision conditions including retinal disorders, focusingdisorders, muscular disorders and other afflictions can be measured andtracked. If a user's vision has deteriorated substantially, the user canbe notified. Data from multiple measurement and training sessions andfrom different games can be combined. Security techniques can be appliedto ensure a properly operating system.

Although the invention has been described in detail, those skilled inthe pertinent art should understand that they can make various changes,substitutions and alterations herein without departing from the scope ofthe invention in its broadest form.

1. A binocular viewer having left and right display elements andcomprising: a variable focal depth optical subsystem located in anoptical path between said display elements and a user when said useruses said binocular viewer; and a control input coupled to said left andright display elements and said variable focal depth optical subsystemand configured to receive control signals operable to place images onsaid left and right display elements and vary a focal depth of saidvariable focal depth optical subsystem.
 2. The binocular viewer asrecited in claim 1 wherein said binocular viewer is part of a visionmeasurement and training system that includes a computer coupled to saidcontrol input and configured to provide said control signals.
 3. Thebinocular viewer as recited in claim 2 wherein said computer is integralwith said binocular viewer.
 4. The binocular viewer as recited in claim2 wherein said vision measurement and training system further includes ahuman input device, said control signals being at least partially basedon input received from said human input device.
 5. The binocular vieweras recited in claim 1 wherein said images constitute video graphics andare based at least in part on input received from said user.
 6. Thebinocular viewer as recited in claim 1 wherein said images cooperate toform a stereoscopic image and said control signals are operable to varyin concert an apparent depth of said stereoscopic image and a focaldepth of said variable focal depth optical subsystem.
 7. The binocularviewer as recited in claim 1 wherein said images include at least onefeature unique to one of said left and right display elements.
 8. Thebinocular viewer as recited in claim 1 further comprising an eyetracking device.
 9. The binocular viewer as recited in claim 1 furthercomprising alignment features configured to indicate an alignment ofsaid binocular viewer with respect to said user.
 10. The binocularviewer as recited in claim 9 wherein said binocular viewer is configuredto transmit signals indicating said alignment.
 11. The binocular vieweras recited in claim 10 wherein said alignment is employed to prompt saiduser to realign said binocular viewer.
 12. The binocular viewer asrecited in claim 10 wherein said alignment is employed to adjust datacollected from said user.
 13. The binocular viewer as recited in claim 2wherein said computer is configured to store and compare data pertainingto said binocular viewer and generate a user alert based thereon. 14.The binocular viewer as recited in claim 1 wherein said binocular vieweris configured to provide a coded message that identifies said binocularviewer.
 15. A method of measuring and training vision, comprising:viewing left and right display elements of a binocular viewer through avariable focal depth optical subsystem associated therewith; andreceiving control signals into a control input of said binocular viewer,said control input coupled to said left and right display elements andsaid variable focal depth optical subsystem, said control signalsoperable to place images on said left and right display elements andvary a focal depth of said variable focal depth optical subsystem. 16.The method as recited in claim 15 wherein said binocular viewer is partof a vision measurement and training system that includes a computercoupled to said control input and configured to provide said controlsignals.
 17. The method as recited in claim 16 wherein said computer isintegral with said binocular viewer.
 18. The method as recited in claim16 wherein said vision measurement and training system further includesa human input device, said control signals being at least partiallybased on input received from said human input device.
 19. The method asrecited in claim 15 wherein said images constitute video graphics andare based at least in part on input received from said user.
 20. Themethod as recited in claim 15 wherein said images cooperate to form astereoscopic image and said control signals are operable to vary inconcert an apparent depth of said stereoscopic image and a focal depthof said variable focal depth optical subsystem.
 21. The method asrecited in claim 15 wherein said images include at least one featureunique to one of said left and right display elements.
 22. The method asrecited in claim 15 further comprising an eye tracking device.
 23. Themethod as recited in claim 15 further comprising alignment featuresconfigured to indicate an alignment of said binocular viewer withrespect to said user.
 24. The method as recited in claim 23 wherein saidbinocular viewer is configured to transmit signals indicating saidalignment.
 25. The method as recited in claim 24 wherein said alignmentis employed to prompt said user to realign said binocular viewer. 26.The method as recited in claim 24 wherein said alignment is employed toadjust data collected from said user.
 27. The method as recited in claim16 wherein said computer is configured to store and compare datapertaining to said binocular viewer and generate a user alert basedthereon.
 28. The method as recited in claim 15 wherein said binocularviewer is configured to provide a coded message that identifies saidbinocular viewer.
 29. A vision measurement and training system,comprising: a binocular viewer having left and right display elementsand a variable focal depth optical subsystem located in an optical pathbetween said display elements and a user when said user uses saidbinocular viewer; a computer coupled to said control input andconfigured to provide control signals to said binocular viewer that areoperable to place images on said left and right display elements andvary a focal depth of said variable focal depth optical subsystem; and ahuman input device, said control signals being at least partially basedon input received from said human input device.
 30. The system asrecited in claim 29 wherein said computer is integral with saidbinocular viewer.
 31. The system as recited in claim 29 wherein saidimages constitute video graphics and are based at least in part on inputreceived from said user.
 32. The system as recited in claim 29 whereinsaid images cooperate to form a stereoscopic image and said controlsignals are operable to vary in concert an apparent depth of saidstereoscopic image and a focal depth of said variable focal depthoptical subsystem.
 33. The system as recited in claim 29 wherein saidimages include at least one feature unique to one of said left and rightdisplay elements.
 34. The system as recited in claim 29 furthercomprising an eye tracking device.
 35. The system as recited in claim 29further comprising alignment features configured to indicate analignment of said binocular viewer with respect to said user.
 36. Thesystem as recited in claim 35 wherein said binocular viewer isconfigured to transmit signals indicating said alignment.
 37. The systemas recited in claim 36 wherein said alignment is employed to prompt saiduser to realign said binocular viewer.
 38. The system as recited inclaim 36 wherein said alignment is employed to adjust data collectedfrom said user.
 39. The system as recited in claim 29 wherein saidcomputer is configured to store and compare data pertaining to saidbinocular viewer and generate a user alert based thereon.
 40. The systemas recited in claim 29 wherein said binocular viewer is configured toprovide a coded message that identifies said binocular viewer.
 41. Abinocular viewer having left and right display elements and comprising:a control input coupled to said left and right display elements andconfigured to receive control signals operable to place images on saidleft and right display elements, said images including at least onefeature unique to one of said left and right display elements.
 42. Thebinocular viewer as recited in claim 41 further comprising a variablefocal depth optical subsystem located in an optical path between saiddisplay elements and a user when said user uses said binocular viewer,said control signals being further operable to vary a focal depth ofsaid variable focal depth optical subsystem.
 43. The binocular viewer asrecited in claim 41 wherein said binocular viewer is part of a visionmeasurement and training system that includes a computer coupled to saidcontrol input and configured to provide said control signals.
 44. Thebinocular viewer as recited in claim 43 wherein said computer isintegral with said binocular viewer.
 45. The binocular viewer as recitedin claim 43 wherein said vision measurement and training system furtherincludes a human input device, said control signals being at leastpartially based on input received from said human input device.
 46. Thebinocular viewer as recited in claim 41 wherein said images constitutevideo graphics and are based at least in part on input received fromsaid user.
 47. The binocular viewer as recited in claim 41 wherein saidimages cooperate to form a stereoscopic image and said control signalsare operable to vary an apparent depth of said stereoscopic image. 48.The binocular viewer as recited in claim 41 further comprising an eyetracking device.
 49. The binocular viewer as recited in claim 41 furthercomprising alignment features configured to indicate an alignment ofsaid binocular viewer with respect to said user.
 50. The binocularviewer as recited in claim 49 wherein said binocular viewer isconfigured to transmit signals indicating said alignment.
 51. Thebinocular viewer as recited in claim 50 wherein said alignment isemployed to prompt said user to realign said binocular viewer.
 52. Thebinocular viewer as recited in claim 50 wherein said alignment isemployed to adjust data collected from said user.
 53. The binocularviewer as recited in claim 43 wherein said computer is configured tostore and compare data pertaining to said binocular viewer and generatea user alert based thereon.
 54. The binocular viewer as recited in claim41 wherein said binocular viewer is configured to provide a codedmessage that identifies said binocular viewer.
 55. A method of measuringand training vision, comprising: receiving control signals into acontrol input of said binocular viewer, said control input coupled tosaid left and right display elements and said variable focal depthoptical subsystem; and placing images on said left and right displayelements, said images including at least one feature unique to one ofsaid left and right display elements.
 56. The method as recited in claim55 further comprising viewing left and right display elements of abinocular viewer through a variable focal depth optical subsystemassociated therewith, said control signals being further operable tovary a focal depth of said variable focal depth optical subsystem. 57.The method as recited in claim 55 wherein said binocular viewer is partof a vision measurement and training system that includes a computercoupled to said control input and configured to provide said controlsignals.
 58. The method as recited in claim 57 wherein said computer isintegral with said binocular viewer.
 59. The method as recited in claim57 wherein said vision measurement and training system further includesa human input device, said control signals being at least partiallybased on input received from said human input device.
 60. The method asrecited in claim 55 wherein said images constitute video graphics andare based at least in part on input received from said user.
 61. Themethod as recited in claim 55 wherein said images cooperate to form astereoscopic image and said control signals are operable to vary inconcert an apparent depth of said stereoscopic image and a focal depthof said variable focal depth optical subsystem.
 62. The method asrecited in claim 55 further comprising an eye tracking device.
 63. Themethod as recited in claim 55 further comprising alignment featuresconfigured to indicate an alignment of said binocular viewer withrespect to said user.
 64. The method as recited in claim 63 wherein saidbinocular viewer is configured to transmit signals indicating saidalignment.
 65. The method as recited in claim 64 wherein said alignmentis employed to prompt said user to realign said binocular viewer. 66.The method as recited in claim 64 wherein said alignment is employed toadjust data collected from said user.
 67. The method as recited in claim57 wherein said computer is configured to store and compare datapertaining to said binocular viewer and generate a user alert basedthereon.
 68. The method as recited in claim 55 wherein said binocularviewer is configured to provide a coded message that identifies saidbinocular viewer.
 69. A vision measurement and training system,comprising: a control input coupled to said left and right displayelements and configured to receive control signals operable to placeimages on said left and right display elements, said images including atleast one feature unique to one of said left and right display elements;a computer coupled to said control input and configured to providecontrol signals to said binocular viewer that are operable to placeimages on said left and right display elements; and a human inputdevice, said control signals being at least partially based on inputreceived from said human input device.
 70. The system as recited inclaim 69 further comprising a binocular viewer having left and rightdisplay elements and a variable focal depth optical subsystem located inan optical path between said display elements and a user when said useruses said binocular viewer, said control signals being further operableto vary a focal depth of said variable focal depth optical subsystem.71. The system as recited in claim 69 wherein said computer is integralwith said binocular viewer.
 72. The system as recited in claim 69wherein said images constitute video graphics and are based at least inpart on input received from a user.
 73. The system as recited in claim69 wherein said images cooperate to form a stereoscopic image and saidcontrol signals are operable to vary in concert an apparent depth ofsaid stereoscopic image and a focal depth of said variable focal depthoptical subsystem.
 74. The system as recited in claim 69 furthercomprising an eye tracking device.
 75. The system as recited in claim 69further comprising alignment features configured to indicate analignment of said binocular viewer with respect to a user.
 76. Thesystem as recited in claim 75 wherein said binocular viewer isconfigured to transmit signals indicating said alignment.
 77. The systemas recited in claim 76 wherein said alignment is employed to prompt auser to realign said binocular viewer.
 78. The system as recited inclaim 76 wherein said alignment is employed to adjust data collectedfrom a user.
 79. The system as recited in claim 69 wherein said computeris configured to store and compare data pertaining to said binocularviewer and generate a user alert based thereon.
 80. The system asrecited in claim 69 wherein said binocular viewer is configured toprovide a coded message that identifies said binocular viewer.